
STUDIES ON A DRAINED MARSH SOIL 
UNPRODUCTIVE FOR PEAS 



A THESIS ACCEPTED IN PARTIAL SATISFACTION OF 

THE REQUIREMENTS FOR THE DEGREE OF 

DOCTOR OF PHILOSOPHY 

AT THE UNIVERSITY OF CALIFORNIA 



PAUL STBERE BURGESS 



UNIVERSITY OF CALIFORNIA PUBLICATIONS 

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Vol. 4, No. 11, pp. 339-396, 21 figures in text June 30, 1922 



STUDIES ON A DRAINED MARSH SOIL 
UNPRODUCTIVE FOR PEAS 



PAUL S. BURGESS 



UNIVERSITY OF CALIFORNIA PRESS 
BERKELEY, CALIFORNIA 



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Vol. 4, No. 11, pp. 339-396, 21 figures in text June 30, 1922 



STUDIES ON A DRAINED MARSH SOIL 
UNPRODUCTIVE FOR PEAS 

BY 

PAUL S. BURGESS 



CONTENTS 

PAGE 

Introduction _ 339 

Statement of the Problem 341 

Methods employed 341 

The field experiments 345 

The soil type 345 

Variability of the field soil _ : 349 

Results of the plot experiments 351 

The greenhouse experiments 358 

Objects of the pot experiments 360 

Treatments employed 361 

Crop yields 367 

Soil extraction studies _ _ 376 

Summary _ _ 387 

Conclusions _ _ 390 

Literature cited 393 



INTKODUCTION 

The unparalleled progress made during recent years in chemistry 
and physics has given decided impetus to the development of scientific 
methods in soil science and in the science of plant physiology, which 
are rapidly supplanting the older, more empirical methods of experi- 
mentation. 28 * New and improved procedures are constantly appearing 
for the elucidation of problems involving a lack of soil fertility, while 
the fundamental questions of plant nutrition are being investigated 
with thoroughness and the results interpreted with discriminating 
care. 



Literature cited, pp. 393 to 396. 



340 University of California Publications in Agricultural Sciences [Vol. 4 

At present, the more important factors recognized as bringing 
about a state of infertility in soils are : 

1. Untoward climatic conditions. 

2. Too slight a concentration, at some time during the growth 
period, of one or more essential mineral elements dissolved in the soil 
solution, or the lack in the solution of a proper physiological balance 
of ions or salts. 

3. The presence of substances dissolved in the soil solution which 
may be toxic to plant growth; these may be either of organic or 
inorganic nature. 

4. Poor physical conditions obtaining in either the surface or the 
subsoil. 

5. A condition of either abnormal or subnormal activity on the 
part of certain of the soil's micro-organic population. 

6. The absence of sufficient quantities of organic materials under- 
going active decomposition. 

Until comparatively recently, agricultural chemists and students 
of plant nutrition have accepted the earlier and more obvious explana- 
tions of most of these facts without question, while the newer concep- 
tions went unproved and unchallenged. Now, however, studies of 
cell permeability are being made, the questions of antagonism between 
ions, and of proper physiological balance between salts in both soils 
and solution cultures are being considered, while explanations of 
such observations are being advanced. The rapidity with which a 
soil is able to replenish or renew solutes absorbed from its solution, 
as well as the total concentration at any given time during the growth 
period, is now recognized as of extreme importance to continued crop 
production. The use of the conductivity apparatus and the cryoscopic 
method has given much valuable comparative data along these lines, 
and has opened fields heretofore, unexplored, while delicate quantita- 
tive methods have also been perfected in this connection. Great ad- 
vances have recently been made in the study of the nature of soil 
acidity as well as in methods for its accurate determination. And 
finally, the recent investigations in the realm of soil colloids — the effects 
upon the colloids of salt applications, as well as the direct effects of 
the colloids themselves in regulating the concentration of the soil's 
solution, and in modifying its moisture relations — should receive 
merited attention. 

Armed with this knowledge, the soil scientist is today better able 
than ever to cope with the many obscure and puzzling problems of 



1922] Burgess: Studies on Marsh Soil Unproductive for Peas 341 

low productivity in soils, which, although everywhere encountered, 
are especially apparent in the more arid or semi-arid sections of this 
country. The application of these modern methods to the solution of 
practical field problems now demands our attention if their benefits 
are to be of direct value to the practice of agriculture. To this end, 
the experiments herein described were undertaken. 



Statement of the Problem 

Large areas of tidewater and overflow lands bordering the San 
Pablo and San Francisco bays and the Sacramento and San Joaquin 
rivers have in the past been drained and are at present used to grow 
a variety of crops. Certain areas within these reclaimed sections, 
varying in extent from an acre to many hundreds of acres, are unpro- 
ductive for certain crops. The study discussed in this paper deals 
with a careful investigation of one partially unproductive area com- 
prising about a thousand acres, located at Ignacio, California, on 
the property of the California Packing Corporation. The owners of 
this ranch were especially desirous of growing peas for canning pur- 
poses on the land under experiment, but have had very poor crops 
during the past few years. The peas ordinarily sprout and come 
up well, but when five or six inches high, turn yellow and gradually 
die. A few plants of each crop always mature, but hardly a third of a 
normal crop usually is harvested. "When we consider that there are 
thousands of acres of similar lands in California which have been 
drained and brought under cultivation at great expense, the importance 
of a careful and thorough study of this problem can hardly be over- 
emphasized. 

METHODS EMPLOYED 

As has been stated, one of the main objects of the present investiga- 
tion was to test the applicability of certain modern methods of soil 
research to the solution of a practical field problem. Among those 
methods which have recently come into considerable prominence may 
be cited the periodical-water-extraction procedure, which has been 
largely developed and standardized by the work of Burd, 5 Hoagland, 21 
and Stewart. 44 The water extraction idea for soil investigations is 
not a new one. It has been used in Europe for over sixty years,* and 



An extensive bibliography is given by Stewart. 44 



342 University of California Publications in Agricultural Sciences [Vol. 4 

twenty years ago in this country, King 25 - 26 applied it to comparative 
fertility work in the field. Also, in the method proposed by Burd and 
his associates the extraction procedure and certain other details are 
quite similar to those used by our Federal Bureau of Soils many years 
ago. The difference between the two lies in the manner of application 
to the problem, and in the method of interpreting the results. One of 
the chief points of weakness attaching to the procedures of the earlier 
workers, and never satisfactorily overcome by them, has now been 
surmounted through the careful and painstaking work of Stewart, 44 
Hibbard, 19 ' 20 and others. I refer to methods of chemical analysis of 
the soil extract. In the earlier work, analytical methods were usually 
far too crude to differentiate between the slight differences often obtain- 
ing. Inaccurate colorimetric methods were then the rule. Today, 
these have largely been supplanted by volumetric and gravimetric 
procedures which insure more accurate results. The general method 
of experimentation mentioned above is given in detail by Stewart. 44 

During the past few years several field tests with fertilizers have 
been made upon the soil under study. The application of lime has 
occasionally increased yields somewhat, and the addition of super- 
phosphate has consistently improved conditions, although the cost of 
the applications has not always been met. A preliminary examination 
made by the writer showed the soil to be very acid in reaction, while 
the deeper layers of the subsoil carried large quantities of the ' ' white 
alkali" salts, notably sulfates. 

With the results and methods just discussed in mind, it was decided 
to conduct two series of experiments: first, a set of plot tests in the 
field, applying superphosphate to certain plots and liming others to 
neutrality, proper checks being maintained ; and, second, a pot experi- 
ment with various soil amendments, to be carried out in the greenhouse 
on the campus of the University of California ; the same soil to be used 
and peas to be grown in both cases. The two crops were to be planted 
at the same time, and soil samples were to be drawn periodically 
from each, extracted and analyzed. Soil reaction under the growing 
crops was also to be closely followed, while alkali determinations were 
to be made from time to time in the field soil. The presence or absence 
of soluble organic soil toxins could also be noted by the application of 
an excess of CaC0 3 , for Truog and Sykora 45 have shown such poisonous 
constituents to be rendered innocuous in soils by the complete neutrali- 
zation of soil acidity as well as by the use of certain other soil amend- 
ments. 



1922] Burgess: Studies on Marsh Soil Unproductive for Peas 343 

Both the field and the pot soils were sampled every four weeks 
during - the growing period except as noted below. A sample was 
drawn from directly beneath the row of growing plants, from four 
places in each plot (see fig. 1), care being taken to obtain a repre- 
sentative sample down to a depth of 7 inches (surface soil). The 
twelve individual samples from the checks and a like number from the 
phosphate plots were then mixed very thoroughly and quartered down 
for the final composite samples. These were brought at once to the 
laboratory, passed through a 2 mm. sieve, and placed in tight Mason 



Toflcriz Plots 


*6 


• 


t 



1 


#5 if-A) ° 


J 



\ 


#4. 




• 


#3 fa) ' 


; 




*2 




1 






ZIS,' 







Fig. 1. — Method of sampling plot soils. 

jars, after withdrawing sufficient soil for moisture determinations. 
The proper amounts of the moist soils, the percentages of moisture 
being taken into consideration, were then weighed out to make 300 g. 
of water-free soil, to which sufficient distilled water was added to 
bring the proportion of water to soil up to exactly 5 to 1. The mix- 
tures of soil and water were now shaken for one hour in an end- 
over-end shaking machine, running at a speed of 7 revolutions per 
minute. Settling was allowed to take place overnight, after which the 
supernatant liquids were siphoned off and filtered through Pasteur- 
Chamberland filters. The resulting clear solutions were used for 
analysis by methods which will be given later. Hydrogen-ion deter- 
minations were made upon portions of the moist soils as soon as 
received at the laboratory. The hydrogen electrode described by 
Sharp and Hoagland 42 was employed. 



344 University of California Publications in Agricultural Sciences [Vol. 4 

111 the greenhouse pot experiment a sharp small-bore 18-inch cheese 
trier was used in sampling, each core being taken from the entire 
depth of soil. In order to obtain sufficient soil for the water extrac- 
tions, it was necessary to take three cores from each pot at each 
sampling. The resulting holes were always filled with similar dry, 
untreated soil. Proper precautions were employed to avoid subse- 
quent sampling in the same places. The moist soils were placed at 
once in tight Mason jars and hydrogen-ion determinations and extracts 
were subsequently made in exactly the same way as described for the 



0000000000©0©00© 



000000000000000© 



Fig. 2. — Arrangement of pots in greenhouse experiment. 

field samples. Conductivity measurements were made upon the ex- 
tracts at each sampling. The simple Kohlrausch conductivity outfit 
was employed. A detailed description of the apparatus, together with 
conversion tables, is given by Oswald and Luther 39 (pp. 461-477). 
The specific resistances (in ohms), rather than their reciprocals, the 
specific conductivities, have been employed in the work hereafter 
reported. 

The clear soil extracts were regularly analyzed for the following 
ions, Ca, Mg, K, P0 4 and N0 3 , supplemented by occasional deter- 
minations of S0 4 , CI, and Al. Carbonates and bicarbonates were 
usually absent except where lime was used. The P0 4 -, Ca-, and K-ions 
were determined in accordance with the methods proposed by Stewart* 4 
(pp. 328, 329), except that 600 cc. aliquots were found necessary in 
the case of P0 4 -ion, while 400 cc. portions were used for Ca and K. 



1922] Burgess: Studies on Marsh Soil Unproductive for Peas 345 

Nitrates and chlorides were run by the phenoldisulphonic acid method 
and by titration with a standard silver nitrate solution, respectively. 
These methods are essentially those widely used in sanitary water 
analysis. 1 Magnesium was determined gravimetrically as the pyro- 
phosphate in the nitrate from the calcium oxalate precipitate, after 
first evaporating to dryness and burning off ammonium salts. Sul- 
fates were determined gravimetrically,' weighing as BaS0 4 . Six hun- 
dred cc. aliquots of the original soil extracts were first evaporated to 
dryness, burned off, and taken up in very dilute hydrochloric acid 
before precipitation with barium chloride. The water-soluble sodium, 
silica, and aluminum were occasionally determined. In all cases ali- 
quots were taken large enough to make possible the use of standard 
gravimetric procedures. 

At the beginning of the work many determinations were made 
upon identical extracts in order to check up the results as regards 
accuracy of duplication. As a ride, the larger the amounts of the 
various ions present, the more accurate would be the determinations. 
For instance, in the case of K, when that ion was present above 
40 p. p. m. (as was usually the case), duplicate determinations in- 
variably checked within less than 3 p. p. m. In other words, the per- 
centage variation between duplicates was here under 8 per cent. 
Better checks than this were usually obtained with Ca,. Mg, N0 3 , and 
CI, while with P0 4 , duplicates might differ by 1 p. p. m. when present 
in quantities of less than 5 p. p. m. The very small amounts of phos- 
phorus always present in these soil extracts made this element un- 
usually difficult to determine accurately. Sulfates always checked 
well in duplicate determinations. 

Stewart 44 (pp. 332, 333) has discussed very fully the form, or 
method, of recording final results, and until more is definitely known 
about the true soil solution, it seems best to the writer, also, to express 
all results as "parts per million of dry soil." This procedure has 
been followed throughout. 



THE FIELD EXPEEIMENTS 

The Soil Type ' 

The soil at Ignacio has been formed by the deposition of clay and 

very fine silt brought down by the Sacramento River. It is a light 

drab clay loam underlain at a depth of six to seven inches by a very 

deep, almost impervious, clay subsoil of lighter color. Neither the 



346 University of California Publications in Agricultural Sciences [Vol. 4 

surface nor the subsoil contains gritty particles of any kind and when 
wetted, both are extremely smooth, plastic, and sticky. Aeration is 
thus always poor and deep root development impossible. The apparent 
specific gravity of the surface soil when air dried and heavily com- 
pacted is 0.970. An acre to a depth of 6 inches thus weighs about 
1,320,000 pounds or 660 tons. Its light weight is due chiefly to the 13 
per cent of organic matter which it contains. The total water holding 
capacity (Hilgard method) is 104% of the moisture-free soil. The 
optimum moisture holding capacity is thus not far from 50% while 
the hygroscopic coefficient is 14%. 

Chemically, the soil presents a number of very interesting features. 
An analysis made by the Hilgard method (digestion for 40 hours at 
100° C. in HC1, sp. gr. 1.115) on a representative composite sample 
from the poor area under study appears in Table I. Only those ele- 
ments important to a discussion of plant nutrition were determined. 
The table also gives the amounts, in parts per million, of the various 
ions (computed as the oxides for comparison) soluble in water, deter- 
mined by the methods previously described. 



TABLE I 

Chemical Analysis of Ignacio Soil 

(Eedueed to water-free basis) 

Strong Acid Water- 
Soluble Per Soluble 
Cent p. p. m. 

Insoluble matter (Si0 2 ) 58.60 55 

Potash (K,0) 0.23 54 

Soda (Na,0) 286 

Lime (CaO) 0.66 125 

Magnesia (MgO) 1.34 75 

Iron (FeA,) -| none 

Alumina (A1 2 3 ) f 2L15 24 

Phosphoric Acid (P»0 5 ) 0.25 4 

Sulfuric Acid (S0 3 ) 0.62 400 

Total nitrogen (N) 0.36 

Nitrates (N0 3 ) 150 

Chlorine (CI) X00 

Loss on ignition (volatile) 13.25 

Manganese was practically absent, as were also carbonates and biearbonates. 
Negative tests were noted for ferrous salts. 

These results are inserted merely to show the general chemical 
composition and the relative solubilities of this soil. It is interesting 
to observe the reversed "lime-magnesia ratio" when total percentages 
of these compounds are compared with their water-soluble portions; 



1922] Burgess: Studies on Marsh Soil Unproductive for Peas 347 

also that the phosphoric acid, although not low in total percentage, is 
but very slightly soluble in water. High amounts of available potassium 
as well as the presence of considerable quantities of water-soluble 
aluminum are also shown. 

As this soil was at one time below the level of San Pablo Bay, it 
was thought desirable at the inception of the work to make a careful 
alkali survey of the area, especially of that portion of it where it was 
later planned to conduct the field experiment. Accordingly, about 
40 samples of surface soil were taken. Several borings were also made 
to a depth of 5 feet, the 1-foot samples being segregated and quanti- 
tatively analyzed for water-soluble chlorides and sulfates. Carbonates 
were absent. Bicarbonates were present in traces only. Table II 
presents the data secured. The figures for the surface soil are averages 
of 40 analyses, all of which agreed fairly closely. The subsoil samples 
(except top foot) are averages of duplicate borings. The number of 
samples averaged appears in the table. 

TABLE II 

Alkali Determinations 

NaCI Na.SOj 

Per Cent.* Per Cent.* 

Surface, 6 to 7 inches (40 samples) 0.018 0.066 

Sub-soil, 1st foot (20 samples) 100 .180 

Sub-soil, 2d foot (2 samples) .150 Heavy testt 

Sub-soil, 3d foot (2 samples) .450 Heavy test 

Sub-soil, 4th foot (2 samples) .710 Heavy test 

Sub-soil, 5th foot (2 samples) .880 Heavy test 

The percentages of alkali present in the surface soil, although con- 
sidered small, may possibly approach toxic concentrations where limited 
moisture conditions prevail. The large quantities of soluble salts in the 
subsoil probably exert, no direct effect, for plants are seldom able to 
root there below 12 inches on account of the impervious, compact con- 
dition of. the soil. That alkali and subsequent leaching have in 
the past contributed to these untoward conditions is probable. The 
work of Sharp, 41 as well as that of Hager, 15 has shown that soils, espe- 
cially heavy clays, once saturated with solutions of soluble salts, or 
inundated with sea water and later washed free, are almost invariably 
left in a very poor and impervious physical condition. 

* Percentages figured to dry soil basis. The surface soil contained 6% water 
(air dry), while the subsoil carried an average of 34% water when received at 
the laboratory. 

t The writer did not quantitatively determine the sulfates in these samples. 



348 University of California Publications in Agricultural Sciences [Vol. 4 

The next factor to receive attention was soil reaction. Peas were 
to be grown and, in the past, a neutral or slightly alkaline reaction has 
been advocated for this crop. The Ignacio soil was found to be ex- 
tremely acid. The hydrogen-ion concentration, as determined on a 
large number of fresh field samples, gave an average exponential value 
of P H = 4.46. A preliminary experiment to ascertain the approximate 
lime requirement was performed after the method of electrometric 
titration with a standard solution of Ca(0H) 2 as proposed by Sharp 
and Hoagland. 42 Considering an acre-six-inches of this soil to weigh 
660 tons (see above), it was found that 4 tons of calcium carbonate 
were immediately required to neutralize the concentration of hydrogen- 
ion present.* An experiment was now set up using 100-gram por- 
tions of the field soil and thoroughly mixing each with different 
amounts of pure CaC0 3 . Optimum moisture conditions were main- 
tained. Table III shows the lime treatments, together with the P H 
values as determined from time to time. 









TABLE III 














Lime Requirement 


OF 


Field Soil 








Tons 
CaC0 3 
per-Acre 


Grams 

CaCO-, 

per 100 

Grams Soil 








Ph 






Number 


After 
1 week 




After 
1 month 




After 
5 months 


After 
7 months 


i 


3 


0.45 


6.3 




5.7 




5.5 


5.4 


2 


4 


0.60 


7.0 




6.0 




5.9 


5.9 


3 


5 


0.75 


7.1 




5.3 




6.1 


5.5 


4 


6 


0.90 


7.2 




6.6 




6.6 


6.5 


5 


8 


1.20 


7.4 




7.1 




7.2 


7.1 


6 


10 


1.50 


7.6 




7.2 




7.2 


7.2 



Considering P H = 7 to indicate a state of neutrality, a glance at 
this table shows that a field application of 7 or 8 tons of lime carbonate 
per acre would be necessary to insure a slightly alkaline soil reaction 
for approximately the growing period of a crop. The fact that larger 
and larger amounts of lime are required upon standing would indicate 
that hydrogen-ions are being progressively and rapidly formed. This 
may be due to a decomposition of organic matter with subsequent 
formation of nitric acid and the less soluble organic acids, to silicate 
degradation, or to the hydrolysis of soluble aluminum compounds. 



* Recent work 4 . 2i has intimated that there may be a relation between 
Ph and lime requirement, whereby the latter may be indirectly and rapidly 
determined, but it appears to the writer, as well as to Knight, 2 ? that much 
work still remains to be done before any general comparisons are possible. 



1922] 



Burgess: Studies on Marsh Soil Unproductive for Peas 



Variability of the Field Soil 
It is in no wise the intention of the writer to enter into a detailed 
discussion of the factor of variability as applied to the study of field 
soils. The work herein reported was planned for other purposes. 
Variability studies have been recently attempted by Waynick 47 and 
by Waynick and Sharp 48 with some measure of success. That seem- 
ingly uniform soils may vary greatly both chemically and biologically 
within very small areas has been well and forcibly brought out by these 
investigators, and, as an excellent opportunity was here presented for 
obtaining further data along this line (where water extracts were 
concerned), a number of analyses are reported showing, for the field 
soil under discussion, the varying tendencies of the "total soluble 
solids," the Ca-, K-, N0 3 -, and the Cl-ions. The location chosen for 
the field plot experiment was the area whence these samples came 
and was in all respects as uniform in texture, color, and appearance 
as one could well find. It was unusually level, being comparatively 
free from slight local elevations or depressions so often present in 
otherwise uniform fields. For miles in all directions but slight visible 
differences could be detected. The locations of samples are shown in 
the accompanying diagram of the field plots. 

Diagram op Field Plots 
l-10th acre plots l-5th acre plots 



X 


X 


6 


X 


X 


X 


X 


9 


X 


X 
















X 


X 


5 


X 


X 


X 


X 




X 


X 




X 


X 


4 


X 


X 


X 


X 


8 


X 


X 
















X 


X 


3 


X 


X 


X 


X 




X 


X 




X 


X 


2 


X 


X 


X 


X 


7 


X 


X 
















X 


X 


1 


X 


X 


X 


X 




X 


X 





Table IV presents the analytical results secured. Before com- 
puting the results as presented, they were in each case plotted and 
shown to form a proper frequency curve. This justifies the use of 
the statistical method in connection with these data. 

As will be seen, not all of the 48 samples were analyzed in each 
case, but sufficient determinations were made to show prevailing eon- 



350 Unwersity of California Publications in Agricultural Sciences [Vol. 4 

ditions. As duplicate extractions of the same sample seldom varied by 
more than 8% to 10% for any of the ions determined (and often by 
much less), and as the coefficient of variability (which is nothing more 
than the standard deviation expressed as its percentage of the mean 
or arithmetical average) varies from 12% in the case of K-ion to over 
44% in the case of N0 3 -ion, there can be no doubt that apparently 
uniform field soils are likely to vary greatly from place to place in 
water-soluble constituents; and it is evident that only averages of 
very large numbers of single determinations or analyses of carefully 
composited samples drawn from a considerable number of separate, 
uniformly distributed stations over areas under examination can 
give dependable results or significant differences. Thus the work of 



TABLE IV 

Variability of the Field Soils as Regards Minerals 

(Parts per million of dry soil) 



Calcium- 


Potassium- 


Total Sol. 


Nitrate- 


Chloride- 


Sulfate- 


ion (Ca) 


ion (K) 


Solids 


ion (NOj) 


ion (CI) 


ion (S0i) 


62 


57 


3215 


310 


120 


986 


49 


54 


2540 


265 


111 


520 


51 


44 


2350 


288 


110 


296 


48 


61 


2125 


350 


120 


444 


340* 


44 


3175 


243 


125 


574 


55 


44 


2300 


177 


130 


499 


59 


54 


2300 


199 


120 


355 


59 


44 


1975 


133 


130 


383 


278* 


53 


2500 


221 


125 


316 


92 


56 


2000 


203 


125 


358 


440* 


48 


1950 


350 


111 


432 


55 


44 


1475 


203 


125 


327 


60 


48 


3075 


221 


310* 


381 


55 


55 


2175 


420 


110 


361 


66 


42 


1825 


310 


105 


449 


52 


39 


2675 


265 


95 


358 


62 


44 


1800 


221 


95 


419 


59 


46 


2700 


203 


100 


386 


51 


' 49 


1975 


203 


95 


363 


50 


40 


1525 


111 


93 


367 


70 


49 


1250 


88 


90 


399 


63 


48 


3000 


99 


85 


385 


481* 


42 


1825 


88 


75 


348 


50 


39 




111 


80 


366 


201* 


56 


Mean =2244 ±74 


221 


100 


460 


69 


56 


S.D. =527 ±52 


133 


90 


424 


60 


55 


C.V. =23. 5 ±2.3% 


155 


95 


659 


56 


53 


P.E. = ±355 


111 


100 


378 


87 






97 


90 


388 


75 


Mean =49 ±.67 




97 


85 


658 


69 


S.D. =6±.53 




177 


86 


399 


191* 


C.V. =12.2±1.1% 




115 


90 


644 




P.E. = ±4.0 




177 


100 


392 


Mean =61 ±1.5 






142 


150 


409 


S.D. =10.9±1.1 






97 


95 


611 


C.V. =18±1.7% 






115 


75 


457 


P.E. =±7.4 






350 


85 










155 


100 


Mean =428 ±10.9 








155 


100 


S.D. =95±7.7 








111 


75 


C.V. =22.3 ±1.8% 












P.E. = ±64.4 








Mean = 192 ±9.2 


Mean=102±1.9 










S.D. =86 ±6.4 


S.D.=17.6±1.3 










C.V. =44.8 ±3.4% 


C.V. =17.2±1.3% 










P.E. = ±58.0 


P.E. = ±11.8 





*Omitted from mean. 



1922] Burgess: Studies on Marsh Soil Unproductive for Peas 351 

Waynick and Sharp on soil variability* has been confirmed and shown 
to hold for certain water extractable materials as well as for nitrates, 
total nitrogen and organic carbon. 

Results of the Plot Experiments 

A brief history of the management of the area under study follows : 
1913 and 1914: Reclaimed from salt marsh by diking and drain- 
age. 
1915: Planted to grain hay. Good yields (3 to 3% tons per acre). 
1916 : Planted to peas. Failure. 
1917: About one ton per acre of "beet-lime" (85% CaC0 3 ) added 

and peas again planted. Failure. 
1918 : Planted again to peas. At first the crop came along nicely, 
but about the middle of March, when the peas were two- 
thirds grown, they suddenly began to die out. Small appli- 
cation of lime apparently had little effect. The crop was 
a failure. After the peas failed the land was immediately 
plowed and beans were planted. A very poor crop resulted — 
about 700 pounds per acre. 
1919 : Sugar beets were grown. A poor crop resulted (between 3 

and 4 tons of small beets per acre). 
1920: A large part of the poor land was again planted to sugar 

beets. 
Much care was exercised in locating the experimental plots and in 
their subsequent oversight and treatment. Neither fertilizers nor soil 
amendments had previously been applied to this area, although small 
applications (1 ton per acre) of lime had been used on adjacent sec- 
tions. About one and one-fifth acres (a piece 125x450 feet) was 
measured off during the month of July, 1919, and after the removal 
of a poor crop of sugar beets, was plowed and disked prior to planting. 
Six one-tenth acre plots, 20x218 feet,t were laid out as were also 
three one-fifth acre plots, 40x218 feet (see diagram above). The 
smaller plots were numbered from one to six, and superphosphate 
(18.1% water-soluble and 20.0% total P 2 5 ) at the rate of 1 ton per 



* For a full and detailed account of the statistical method as applied to the 
interpretation of biochemical results the reader is referred to the papers of 
Waynick already cited, to Wood, 50 . 51 and to Davenport. 10 

t The plots were made long and narrow to facilitate working and harvesting 
by standard machinery. Lyonso has also shown that long and narrow plots 
give most dependable results. 



352 University of California Publications m Agricultural Sciences [Vol. 4 

acre was applied to the odd plots while the even ones received no 
treatment (checks). The center one-fifth acre plot (Number 8) was 
left untreated while Number 7 received finely ground limestone 
(99.6% CaC0 3 ) and Number 9, sugar beet lime (87% CaC0 3 ), both 
at the rate of 10 tons per acre. These applications were slightly in 
excess of the lime requirements for the surface soil (see page 348). 
The phosphate and lime applications were thoroughly disked into the 
surface soil about two weeks before planting. 

The peas (Horseford's Market Garden Variety) were planted on 
October 26, 1919, in rows 30 inches apart, one inch apart in the rows. 
There were thus 8 rows in the smaller and 16 rows in the larger plots. 

Since an important part of the plot experiment was the observation 
of the varying concentration of the soil solution under both the fer- 
tilized and the untreated peas (as manifested by periodical analyses 
of soil extracts prepared from carefully taken representative soil 
samples), samples, taken as previously described, were drawn and 
analyzed on September 3, after the plots had been prepared but 
before the superphosphate had been applied, and subsequently as the 
data in Table V show. (See also graphs in figs. 3 and 4.) 

TABLE V 
Periodic Laboratory Data on Field Plot Soils 

Conductivity 
Measurements. 

Specific Determinations of Plant Food Ions (p. p. m. dry soil) 

Dates of in Ohms Ca-Ion Mg-Ion K-Ion N0 3 -Ion PO.,-Ion 

Soils 1 2 121212 1 2 1 ' 2 

9-3-19 3000 3000 61 61 45 45 49 49 150 150 5.2 5.2 

11-3-19 2560 1382 75 153 ■ 46 136 45 99 133 177 5.2 19.5 

1-20-20 2430 1497 54 134 42 109 51 83 155 177 4.6 8.7 

2-21-20 2970 1855 50 160 34 106 47 83 133 133 1.5 4.5 

3-27-20 2495 1792 56 167 52 113 54 83 49 35 2.3 3.7 

4-26-20 3965 2162 26 96 20 74 32 58 5 2.0 3.0 

5-24-20 3258 1895 46 150 37 93 36 54 10 5 2.3 2.8 

In all eases No. 1 = check plots and No. 2 = phosphate-treated plots. 

As the rainfall during the year 1919-1920 was below the normal 
average for Marin Meadows Ranch,* and as the growth of the peas 

* The annual rainfall data for the past seven years, September 1 to Septem- 
ber 1, follows: 

1913-1914 35.79 inches 

1914-1915 32.99 inches 

1915-1916 27.31 inches 

1916-1917 14.19 inches 

1917-1918 9.20 inches 

1918-1919 17.99 inches 

1919-1920 11.39 inches 



1922] Burgess: Studies on Marsh Soil Unproductive for Peas ' 353 

was so largely dependent upon this factor, it was not thought always 
desirable to draw soil samples at exactly four-week intervals. The 
following brief summary shows the sampling dates and correlates with 
these the condition of the peas at those times. 

September 3, 1919: First samples drawn. Plots staked out but no fertilizers 
yet applied. 

November 3, 1919: First sampling since planting. As less than 0.3 of an 
inch of rain had fallen since planting, but few of the seeds had sprouted. 

January 20, 1920: The peas were 2 to 3 inches high and a good stand had 
been secured. Over 4 inches of rain had fallen since last sampling, but 
the nights were cold (often below freezing), and the days were usually 
cloudy and cold. 

February 21, 1920: Less than one inch of rain had fallen since January 
20. The soil was very dry (moisture determinations showed but 27% in 
the surface soil and 42% in the subsoil). The plants had grown but an 
inch or two during the month and were often more or less wilted during 
the middle of the day. The nights were cold. Poor conditions for growth. 
There was no difference between the checks and the phosphate-treated plots. 

March 27, 1920: The plants were looking well. About 3 inches of rain 
had fallen since last sampling. The vines on the check plots were 6 to 
8 inches high while those on the phosphate-treated plots were 10 to 12 inches 
high. The lime-treated plots showed no improvement over the checks. 

April 26, 1920: The plants were looking fairly well, although little rain 
had been recorded during the month past. The vines were covered with 
blossoms and filling pods. There was a noticeable difference in favor of 
phosphate-treated plots although the lime-treated plots showed no gain. 

May 24, 1920: Peas about ready to cut. Vines turning yellow; pods well 
filled and dry. The soil had dried out and was very parched and hard. 
This was the last date of sampling. 

The plots were harvested June 3. The yields obtained are shown 
in Table VI. 

TABLE VI 
Plot Yields 

Gross Weights, 

Dry Peas and Net Weights, 

Vines Dry Peas 

It's, per lbs. per 

lbs. acre lbs. acre 

Average yield per l/ 10 acre plot (cheeks).... 627 6,270 153 1530 

Average yield per y 10 acre plot (superphos- 

P llate ) 820 8,200 200 2,000 

Average yield per y 5 acre plot (checks).... 1,010 5,050 340 1700 

Average yield per % acre plot (sugar beet 

Hme ) - 1,090 5,450 340 1,700 

Average yield per % acre plot (ground 

limestone) _ 1,090 5,450 330 1,650 

It will be seen that liming to neutrality had no effect upon yields. 
This is in accordance with former field observations on this soil. A 
more extended discussion of the effects of the application of lime 



University of California Publications in Agricultural Sciences [Vol. 4 



will be given later in connection with results secured in the green- 
house where moisture conditions were optimum and where a more 
careful chemical control was possible. The superphosphate treatment 
increased the yield of peas by approximately 25 per cent. This 
increase about paid for the treatment, and a future residual effect 
may be expected. Possibly a larger amount of superphosphate would 
have given higher yields, for much was lost due to reversion (see 
below). 





- 


































°o 
o 






°J^ 

^P^ 


^^^f 










a 
o 

3 200 

S 


































0) 


7 


ti& — 


"~ _..._ 












£ 100 








\ 
















\ 












™~ 


_g ^= 


.._ t£[2.'JL 


---- 


^s 




„^ j^-Si 









_ __P2y 






••■■. 


" 





Dates sampled. 

Fig. 3. — Water-soluble materials dissolved from unfertilized plot soils carrying 
pea crop. 

As has been mentioned, the rainfall was subnormal throughout the 
entire growing period. That the low yields secured on both treated 
and untreated plots were attributable in large part to a lack of water 
will be shown by the following test. Pour approximately 50-foot rows 
(two in a phosphate plot and two in a check plot) were chosen at 
random and regularly irrigated* for a period of several weeks 
during the months of February and March. Rapid growth and great 
improvement over those plants not so treated was observed. As heavy 
rains fell during the latter part of March, irrigating was discontinued. 
The beneficial results of these few applications of water during the 
early stages of growth were, however, noticeable up to the time of 
harvesting. 



* Water hauled in a tank wagon. 



1922] 



Burgess: Studies on Marsh Soil Unproductive for Peas 



The curves presented in figures 3 and 4 show graphically the rise 
and fall in concentration of the soil solution under the growing crop. In 
studying these graphs it should be remembered that the superphosphate 
was applied between September 3 and November 3 (see figure 4), and 
that the plants were absorbing nutrients most vigorously during the 
months of March and April. We note first that much greater con- 
centrations of salts prevail throughout the entire period within the 
soils of the fertilized plots. This is clearly depicted by the solid line 



„• 300 




Dates sampled. 

Fig. 4. — Water-soluble materials dissolved from phosphate-treated plot soils 
carrying pea crop. 

representing one-tenth of the specific resistance in ohms. That this 
increased concentration is due in large part not to the superphosphate, 
but to the increased solubility of other ions caused by it within the 
soil itself, is strikingly shown by the Mg and K graphs. This doubt- 
less accounts largely for the greater yields obtained on the phosphate 
plots, for where water is limited, Morgan 37 has shown that transpira- 
tion is necessarily less, and that the enhancing effect of fertilizers 'is 
relatively greatly increased. He states, "All fertilizers, both mineral 
and nitrogenous, have greatly decreased in their relative efficiency fol- 
lowing an increase in soil moisture. The decrease is consistent." It 
is further a well established physiological fact that water is greatly 
economized by increasing the plant's supply of mineral salts (see 
Russel, 40 pages 29, 30). 



356 University of California Publications in Agricultural Sciences [Vol. 4 

Taking up the ions separately, we note that phosphate applications 
have but slightly affected nitrate formation. This is doubtless due 
to excessive soil acidity which dominates nitrification within this soil. 

The yields show that soluble nitrogen is here more than adequate 
for peas. The amounts of potassium and magnesium, soluble in water, 
in this heavy clay soil, have been almost doubled throughout the 
entire growing period by the initial acid-phosphate application. That 
the gypsum present in the superphosphate is largely responsible for 
this increase is shown by results secured in the more carefully con- 
trolled greenhouse experiment (see McCool and Millar 33 in this con- 
nection). As would be expected, both water-soluble calcium and 
phosphorus have been somewhat increased in the soils of those plots 
receiving the soluble phosphate treatments. 

Chlorides and sulfates were periodically determined. As these ions 
were always present in great excess, however, they have not been 
included in Table V nor in the graphs, but have been more properly 
figured as the sodium salts (white alkali), and appear in Table VII. 
An idea has prevailed in the past that occasional increases in the 
amount of alkali present may have been responsible for crop failures. 

TABLE VII 
Periodical Determination op White Alkali in Plot Soils 

Date % NaCl % NaoS0 4 

September 3, 1919 0.018 0.066 

November 3, 1919 '. 025 

January 20, 1920 023 .066 

February 21, 1920 017 .067 

March 27, 1920 032 .060 

• April 26, 1920 017 .050 

May 24, 1920 020 .100 

While the percentages of alkali here noted are doubtless innocuous 
if optimum moisture conditions exist, it is conceivable, as before stated, 
that at times of unusual drought, plants may suffer in the more con- 
centrated soil solution that results, and, while a lack of water is 
directly responsible for this condition, alkali salts may well be con- 
sidered an important indirect or contributing factor. 

Other toxic compounds, as ferrous iron* or soluble aluminum salts, 
here appealed to the writer as being possible causes of infertility. 
"We were, however, unable to secure a positive test for ferrous iron 
in the surface soil. Special samples were taken for these tests, every 

* Certain heavy soils of the Transvaal have been shown by Watt*s to have been 
rendered unproductive by accumulations of ferrous salts. 



1922] Burgess: Studies on Marsh Soil Unproductive for Feas 357 

precaution being used to avoid oxidation in transit. On the other 
hand, water-soluble aluminum was usually found. Large numbers 
of determinations showed it to be present to the extent of 12 to 15 parts 
per millon in the surface soil, while approximately twice these amounts 
were found in the subsoil. 

The considerable literature upon the subject of aluminum toxicity 
has been notably extended during the past two or three years by the 
careful work of Hartwell and Pember, 17 ' 18 Conner, 9 Ames and Schol- 
lenberger, 2 and Miyake. 35 The first-mentioned investigators have 
definitely shown that soluble aluminum compounds exist in toxic con- 
centrations in certain acid soils; that plants differ in their powers of 
resistance to soluble aluminum ; and that such conditions may be readily 
ameliorated by applications of any substance which will precipitate 
aluminum-ion. From data furnished by Hartwell and Pember 18 (page 
266), it is possible to calculate the concentration of soluble aluminum 
present in the acid soils upon which they experimented. This was 
found to be approximately 77 parts of A1 2 3 or 41 parts of soluble 
aluminum per one million parts of dry soil. They extracted using 
slightly different proportions (about 1 to 3) of soil and water than 
did the writer, but the results should be fairly comparable. They 
furthermore found that at least 15 p. p. m. of aluminum in solution 
cultures with growing plants were required to produce signs of tox- 
icity. In the light of these results, it would appear somewhat doubt- 
ful whether the relatively small quantities (12 to 15 p. p. m. of 
aluminum) found in the soil of the Marin Meadows Ranch could be 
entirely responsible for the seriously depleted yields. The other 
authors cited in this connection have shown that amounts of aluminum 
greatly in excess of 15 p. p. m. of soil are necessary to render con- 
ditions toxic for crop plants in soils; and, finally, the plants in our 
own untreated pots, in which this soil was used without drainage, gave 
no indications of aluminum-poisoning. 

To sum up briefly the points brought out by the field plot experi- 
ment, we may conclude with reasonable certainty that, during the past 
season at least, water has been the limiting factor in crop production ; 
that a one-ton application of superphosphate in absence of irrigation 
has increased the yield of peas by approximately 25 per cent; that 
liming to neutrality had practically no effect upon yield, due possibly 
to delayed reaction on account of paucity of rainfall ; and, finally, that, 
inorganic toxins, as alkali, ferrous iron, and aluminum salts, are 
probably at present not directly responsible for lack of productivity. 



University of California Publications in Agricultural Sciences [Vol. 4 



THE GREENHOUSE EXPERIMENTS 

While field trials are generally considered as being the most reliable 
method of solving fertility problems, they are expensive and cumber- 
some, and, as has already been shown, should be executed over a period 
of years to allow for a fair average of climatic conditions. The quicker, 
less expensive, and more controllable pot experiment, as carried out 
in a well equipped greenhouse, is therefore often desirable. Coffey 
and Tuttle, 7 Wheeler, Brown and Hogensen, 49 and others have 
compared pot tests with field trials and have shown them to agree 
remarkably well where certain details of manipulation are followed. 
Furthermore, the ofttimes limiting factors of moisture and tempera- 
ture may be so controlled in greenhouse work as to permit of more 
definite conclusions regarding possible plant food deficiencies. In the 
present work, this method of experimentation was especially adaptable, 
as frequent periodical soil-sampling was required. 

The proper kind and quantity of fertilizer to apply depend as much 
upon the total effect produced within the soil solution as they do upon 
the element or elements directly supplied, for many of the changes 
induced may be indirect. For instance, sodium nitrate, so widely used 
as a source of available nitrogen, may so deflocculate a heavy soil as to 
render it non-productive. Much information is at present available 
in agricultural literature on the effects of additions of fertilizer salts 
and other chemical compounds upon the solubility of soil constituents. 
While a large portion of these data have been secured by subjecting the 
soils studied to artificial laboratory conditions, far removed from those 
actually obtaining in the field, nevertheless many of them have a 
sufficient bearing upon the present work to necessitate reviewing. 
More than seventy articles were read in this connection. However, as 
comprehensive references to the literature accompany the papers of 
Greaves and Carter, 13 Spurway, 43 and Maclntire, 31 it was thought best 
not to burden the reader with an extended review, very little of which 
could be directly compared with data to be subsequently presented, 
but rather to give a brief discussion of the work as a whole, noting 
the points in agreement as well as those at variance with the results 
hereafter given. 

The chief impression made upon the reviewer of the literature 
within this field is the dissimilarity and often contradictory nature of 
results reported. For instance, certain writers have shown that addi- 
tions of sodium nitrate to soils greatly enhance phosphate availability, 



1922] Burgess: Studies on Marsh Soil Unproductive for Peas 359 

while a like number may easily be found who claim that sodium nitrate 
inhibits the solution of phosphates in soils. Similar differences of 
opinion exist regarding the effects of lime and gypsum upon the 
solubility of soil potash. An able discussion of such discrepancies, 
at least in so far as the effects of calcium carbonate and gypsum upon 
soil potassium are concerned, is given by Lipman and Gericke. 29 These 
writers attribute unlike and contradictory results to variations in the 
nature of the mineral content of the soils from different localities. 
The linkages binding potassium within the intricate silicate molecules 
doubtless vary greatly with different mineral complexes, the potassium 
being much more easily replaced by calcium, sodium, or other metallic 
ions in some instances than in others. As this might equally well 
apply to all the elements ordinarily met with in soils, one could hardly 
expect similar results to be obtained in all cases and for all elements. 
In fact, Lipman and Gericke, 20 Spurway, 43 Christie and Martin, 6 and 
many others give data which conclusively show that applications of 
the same salts in similar amounts react differently in different soils. 
Another factor which doubtless also plays a part is soil texture. The 
fine clays and clay loams presenting many times the internal surface 
found in the coarser silts and sands, should, and usually do, yield more 
material to solution. This is probably largely a mechanical factor. 

Taking the recorded data on this subject by and large, the following 
statements seem to be justified in a majority of cases. The normal 
sulfates and chlorides of calcium, magnesium, sodium, and ammonium, 
may enhance the solubility of soil potassium and soil phosphorus, 
although the acid salts act much more strongly, especially in the case of 
the latter element. Nitrates act erratically, but we are fairly safe 
in saying that they usually slightly increase soil potash solubility, 
and exert little effect on soil phosphorus, although we know that the 
calcium phosphates are much more soluble in solutions of nitrates than 
are the iron and aluminum phosphates. The addition of calcium oxide 
usually increases potash solubility while the carbonate often has no 
direct effect. Phosphate solubility is usually depressed by lime appli- 
cations, although this is not universally the case with quicklime, while 
the sulfates of the heavy metals often greatly increase it. Many 
writers have also shown that, under certain conditions, the soil bac- 
teria, especially the nitrifiers, exert a decided solvent action upon the 
insoluble phosphates of both soils and fertilizers. 



360 University of California Publications in Agricultural Sciences [Vol. 4 

Objects of the Pot Experiments 

The objects of the pot experiments hereafter reported were: (1) 
so far as possible to eliminate climate, especially moisture, as a factor 
in crop production upon the soil studied, and to maintain throughout 
the growth period as nearly optimum conditions as possible; (2) to 
note the effects upon the growth of the pea plants, and upon the final 
yields of dried peas, of additions of the several fertilizers and soil 
amendments supplied; (3) to find whether or not such applications of 
chemical compounds influence the solubilities of the soil's constituents 
as manifested by periodical extractions of both planted and fallowed 
soils with distilled water; (4) to ascertain the effect of soluble salt 
applications upon the nodule formation of peas within this acid soil ; 
(5) to ascertain whether or not soil toxins of any kind were inhibiting 
normal growth. 




Dates sampled. 

Fig. 5. — Water-soluble materials dissolved from cropped check pot soils (no 
fertilization). 



1922] 



Burgess: Studies on Marsh Soil Unproductive for Peas 



Treatments Employed 

The experiments were carried out in a well regulated greenhouse. 
The pots used were 5-gallon glazed earthenware crocks about 12 inches 
in diameter and 11 inches deep. No holes were provided for drainage 
as it was desired that no soluble constituents be lost during the growth 
of the crops. The pots were weighed, and water added to optimum at 




Dates sampled. 

Fig. 6. — Water-soluble materials dissolved from cropped gypsum-treated pot 
soils. 



each irrigation. The soil was procured during the month of August 
from the field plots above described, 6 two-bushel sacks of surface soil 
being taken from each of the 6 one-tenth acre plots. It was air-dry 
and dusty to a depth of approximately 6 inches. When received at 
the greenhouse, it was thoroughly mixed by being shoveled over five 
times and twice screened (one-fourth inch mesh) to remove the larger 
clods. Thirteen kilograms were then weighed into each of 64 pots, 
thus providing eight pots for each of the eight different treatments to 
be tested. The additions were made as follows: 



University of California Publications in Agricultural Sciences [Vol. 4 



Pots 1- 8: Checks. No additions. 

Pots 9-16: Gypsum at the rate of 1 T. per acre (20 g. per pot). 

Pots 17-24: CaCO s at the rate of 8 T. per acre (160 g. per pot). 

Pots 25-32: Superphosphate at the rate of 1 T. per acre (20 g. per pot). 

Pots 33-40: NaN0 3 at the rate of 500 lbs. per acre (5 g. per pot). 

Pots 41-48: K»S0 4 at the rate of 500 lbs. per acre (5 g. per pot). 

Pots 49-56: Super. (1 T. per a.) and K,S0 4 (500 lbs. per a.). 

Pots 57-64: Super. (1 T. per a.) and CaCO„ (8 T. per a.). 

As will be observed, the applications here made were in all cases 
consistent with good field practice. The amounts of salts (dry) as 
indicated were thoroughly mixed into the surface six inches of soil 




Dates sampled. 

Fig. 7. — "Water-soluble materials dissolved from cropped ealcium-carbonate- 
treated pot soils. 



1922] Burgess: Studies on Marsh Soil Unproductive for Peas 363 

in each pot, after which the soils were settled into place by an irrigation 
calculated to be optimum (one-half total moisture holding capacity). 
The pots were then allowed to stand for one week before planting. The 
salts applied were "Bakers C. P. Analyzed Chemicals" in all cases 
except the superphosphate, which was the same as that used in the 
field plot experiments. At the same time, a set of six pots of the soil, 
which were to be kept fallow (no crop) were set up. The first six, 
single-salt treatments only were here employed. These fallowed pots 
were subsequently treated in exactly the same way as the cropped pots. 

The peas (Horseford's Market Garden variety) were sown on 
November 10, 1919 ; eight uniform seeds to the pot. A good stand was 
obtained. When the plants were about three inches high, they were 
thinned to four per pot. When 6 to 8 inches high, the peas were 
trellised, using split laths and string. The floor plan of the green- 
house indicating the arrangement of the benches and the pots is shown 
in figure 2. As the plants grew taller and shading was evident at 
certain periods during the day, the practice of changing the pots from 
one bench to the other each week at the time of irrigation was adopted. 

As one of the objects of the work was to ascertain the effects of the 
several salt applications upon soil-mineral solubility, at approximately 
four-week intervals samples of the cropped soils were withdrawn from 
the pots and analyses made in accordance with the detailed methods 
previously given. The results of this work appear in Table VIII and, 
for convenience, are graphically shown in figures 5 to 19. It had been 
planned also to extract and analyze the similarly treated fallowed 
soils each month, but, as the two series will be shown to be hardly com- 
parable, and as time for this large amount of analytical work was 
wanting, the uncropped soils were analyzed but four times during the 
experiment (during October, November, January, and April). The 
results of these analyses appear in Table IX. 

After thinning, and when the plants had reached a height of 6 or 7 
inches, some trouble was experienced with mice. In eight or ten of the 
pots, one or two of the plants were destroyed. This difficulty was 
quickly overcome, but not before some damage had been done. For 
this reason, in Table X, only six pots (out of the eight of each treat- 
ment) giving the highest yields per pot, and having four plants each, 
have been used in computing statistically the final yields obtained, 
although the yields in all of the pots are given.* 



* As stated in the table, a star (*) marks those figures omitted from the 
averages. The data, when plotted, gave uniform frequency curves. 



University of California Publications in Agricultural Sciences [Vol. 4 









TABLE VIII 








Periodic Determinations on 


Cropped, Pot Soils 










Dates of Sampling Soils 






Number 


10-15-19 


11-20-19 


12-18-19 


1-19-20 


2-20-20 


3-20-20 






Acidity expressed 


inP H 






1 


4.46 


4.51 


4.50 


4.48 


4.46 


4.71 


2 


4.46 


4.55 


4.58 


4.50 


4.51 


4.73 


3 


4.46 


7.20 


7.20 


7.39 


7.34 


7.25 


4 


4.46 


4.67 


4.62 


4.62 


4.60 


4.71 


5 


4.46 


4.67 


4.72 


4.53 


4.63 


4.88 


6 


4.46 


4.67 


4.68 


4.67 


4.67 


4.88 


7 


4.46 


4.63 


' 4.63 


4.63 


4.65 


4.80 


8 


4.46 


7.30 
Specific 


7.33 
i Resistance 


7.46 
in Ohms 


7.42 


7.33 


1 


3,000 


2,381 


2,515 


2,752 


3,053 


2,726 


2 


3,000 


1,498 


1,568 


1,517 


1,728 


1,402 


3 


3,000 


1,420 


1,331 


1,325 


1,357 


1,261 


4 


3,000 


1,280 


1,568 


1,856 


2,022 


1,587 


5 


3,000 


2,112 


2,029 


2,131 


2,374 


2,302 


6 


3,000 


2,131 


2,054 


2,400 


2,509 


2,118 


7 


3,000 


1,286 


1,472 


1,523 


1,702 


1,382 


8 


3,000 


1,171 


1,133 


998 


1,088 


1,018 






Calcium 


-ion, parts per million 






1 


60 


49 


35 


34 


41 


25 


2 


■60 


269 


262 


150 


133 


169 


3 


60 


279 


319 


309 


295 


350 


4 


60 


131 


136 


104 


88 


128 


5 


60 


59 


59 


50 


43 


48 


6 


60 


169 


71 


55 


52 


56 


7 


60 


160 


150 


121 


102 


169 


8 


60 


387 


430 


428 


434 


500 






Magnesium-ion, parts per million 






1 


45 


46 


40 


37 


30 


29 


2 


45 


105 


109 


■ 120 


107 


125 


3 


45 


110 


121 


117 


116 


130 


4 


45 


110 


106 


79 


78 


102 


5 


45 


55 


53 


48 


46 


38 


6 


45 


70 


67 


56 


48 


55 


7 


45 


133 


125 


98 


86 


127 


8 


45 


145 


147 


144 


150 


154 






Potassium-ion, parts ; 


per million 






1 


50 


58 


54 


50 


39 


35 


2 


50 


75 


84 


80 


75 


60 


3 


50 


69 


64 


65 


60 


63 


4 


50 


87 


81 


68 


51 


61 


5 


50 


65 


66 


58 


41 


37 


6 


50 


88 


86 


75 


58 


63 


7 


50 


117 


117 


97 


70 


92 


8 


50 


75 


69 


74 


56 


65 



1922] 



Burgess: Studies on Marsh Soil Unproductive for Peas 



TABLE VIII— (Continued) 

Dates of Sampling Soils 











ttllipilljg ^UilO 






Number 


10-15-19 


11-20-19 

Phosphate 


12-18-19 
ion, parts 


1-19-20 
per million 


3-20-20 


3-20-20 


1 


5.2 


3.7 


4.5 


2.3 


3.5 


2.1 


2 


5.2 


6.2 


5.6 


4.0 


4.0 


3.4 


3 


5.2 


6.2 


4.7 


4.5 


4.1 


5.4 


4 


5.2 


8.5 


6.8 


8.4 


7.2 


4.1 


5 


5.2 


5.6 


5.9 


4.1 


4.3 


2.3 


. 6 


5.2 


5.6 


5.6 


4.7 


4.5 


2.0 


7 


5.2 


7.4 


7.0 


7.4 


6.9 


3.2 


8 


5.2 


7.6 


6.7 


7.8 


7.0 


5.6 






Nitrate-ion, parts 


jer million 






1 


150 


89 


267 


204 


35 


5 


2 


150 


80 


239 


213 


44 





3 


150 


338 


621 


532 


266 


84 


4 


150 


156 


221 


177 


27 





5 


150 


488 


488 


400 


177 


30 


6 


150 


178 


266 


177 


44 


5 


7 


150 


156 


266 


177 


40 


7 


8 


150 


196 


485 


443 


266 


156 




Dates sampled. 

Fig. 8. — Water-soluble materials dissolved from cropped superphosphate-treated 
pot soils. 



University of California Publications in Agricultural Sciences [Vol. 4 

TABLE IX 

Periodic Determination's on Fallowed, Pot Soils 

Dates of Sampling Soils 



Treatment 
dumber 


10-15-19 


11-20-19 


1-25-20 


4-1-20 


1 


4.46 


Acidity expressed in 
4.50 


4.43 


4.32 


2 


4.46 




4.55 


4.50 


4.3S 


3 


4.46 




7.20 


7.17 


7.17 


4 


4.46 




4.67 


4.46 


4.46 


5 


4.46 




4.67 


4.45 


4.43 


6 


4.46 




4.67 


4.40 


4.38 


1 


3,000 


Specific 


Eesistance in 
2,380 


Ohms 
lost 


2,04S 


2 
3 


3,000 
3,000 




1,498 
1,420 


lost 
lost 


1,338 

1,011 


4 


3,000 




1,280 


lost 


2,180 


5 


3,000 




2,112 


lost 


1,587 


6 


3,000 




2,131 


lost 


1,754 


1 


60 


Caleium- 


ion, parts per million 
49 72 


81 


2 


60 




269 


250 


209 


3 


60 




279 


514 


512 


4 


60 




131 


112 


99 


5 


60 




59 


104 


100 


6 


60 




169 


128 


104 


1 


Magnesium-ion, parts per million. 
45 46 67 


80 


2 


45 




105 


147 


161 


3 


45 




110 


144 


157 


4 


45 




110 


105 


105 


5 


45 




55 


86 


96 


6 


45 




70 


67 


98 



Potassium-ion, parts per million 

1 50 58 58 59 

2 50 75 S6 84 

3 50 69 65 59 

4 50 87 81 73 

5 50 65 68 72 

6 50 88 86 96 

Phosphate-ion, parts per million 

1 5.2 3.7 3.7 2.3 

2 5.2 6.2 4.1 2.4 
5.2 6.2 4.5 4.3 

4 5.2 8.5 8.4 8.8 

5 5.2 5.6 5.6 4.1 

6 5.2 5.6 4.7 2.3 

Nitrate-ion, parts per million 

1 150 89 400 575 

2 150 80 756 708 
150 338 1,264 1,106 

4 150 156 550 496 

5 150 488 421 940 

6 150 178 355 575 



1922] Burgess: Studies on Marsh Soil Unproductive for Peas 367 

Crop Yields 

The effects of the several soil treatments upon crop yields will first 
be considered. Table X presents this data while a chart showing 
graphically the comparative yields of both total dry matter and 
cured peas appears in figure 20. The "plus or minus" variability 
factors as shown in figure 20 are obtained by multiplying the "prob- 
able error of the mean" in each case (Table X) by three, thus insuring 
practically a thirty to one chance that, in case of repetition, the new 
average yields found will fall within these limits. Those figures also 
help us in determining approximately* whether or not significant 
differences in yields are shown between treatments, t 

The most notable fact impressed upon one who has carefully fol- 
lowed both the field and the greenhouse experiments is that the plants 
grown in the greenhouse under nearly ideal climatic conditions grew 
to at least twice the size and probably, plant for plant, produced nearly 
twice as many peas as those grown in the field at the Marin Meadows 
Ranch. Although the crop on the field plots was above the average, 
the individual plants were small in comparison with any (checks in- 
cluded) grown inside. That water has been one of the important limit- 
ing factors in the field during the past season can hardly be ques- 
tioned. 

The second point to be noticed is the comparatively small increase 
over the check pots due to any of the fertilizer applications. One would 
certainly expect a soil so low in soluble phosphorous or so acid in 
reaction to respond greatly to applications of either soluble phosphates 
or lime, and certainly where both were used. But no such large increases 
are apparent. It is true that enhanced yields follow the application of 

* The exact method of determining whether or not a difference is significant 
is to take the square root of the sum of the squares of the two probable errors 
ot the two means, multiply the resulting figure by 3 and note whether or not 
the product is larger or smaller than the subtracted difference between the two 
means. In case it is smaller, it is safe to conclude that the difference between 
the two means is significant, taking a 30 to 1 chance of securing a similar result 
upon repetition. For example, let us compare the average yield of total dry 
matter secured in the cheek pots with that where gvpsum was applied, and 
find whether or not gypsum actually increased yields: ' 

59.5 ± 0.9 = mean of gypsum pots. 

51.4 ± 1.3 = mean of check pots. 

8.1 ± V 0.9' + 1.3 2 X 3 
= 8.1 ± V 2.50 X 3 
= 8.1 ± 4.6 
As 4.6 is much less than 8.1, we are safe in concluding that there is a significant 
difference shown here between the means, and that the application of gypsum did 
actually slightly increase yields. 

t The scale to the left of fig. 20 should be used in this connection. 



University of California Publications in Agricultural Sciences [Vol. 4 



TABLE X 

Yields of Peas in Greenhouse Pot Experiment 
Treatment No. 1 (Checks) 



Pot Number 
1 


Total Dry Weights 
53.6 


Peas in Pods 
37.1 


Shelled Peas 
29.7 


2 


45.1* 




28.4* 


21.1* 


3 


58.6 




37.7 


30.9 


4 


53.6 




34.9 


28.9 


5 


50.7* 




38.6* 


31.5* 


6 


51.0 




34.5 


28.0 


7 


44.2 




33.9 


26.1 


8 


47.2 




34.1 


28.0 


Mean 


51.4± 


1.3 


35.4±0.4 


28.6±0.4 


Std. Dev. 


4.7± 


1.4 


1.5±0.4 


1.5±0.4 


C. V. 


9.2± 


1.8% 


4.2±0.8% 


5.2±1.0% 


P. E. 


±3.2 




±1.0 


±1.0 




Treatment No. 


2 (Gypsum) 




Pot Number 
9 


Total Dry Weights 
53.7* 


Peas in Pods 
34.3* 


Shelled Peas 
25.5* 


10 


55.8 




37.3 


29.5 


11 


64.3 




37,6 


29.8 


12 


62.9 




35.6 


28.4 


13 


59.0 




33.0 


29.8 


14 


58.1 




36.7 


29.7 


15 


56.6 




33.9 


26.9 


16 


56.9* 




34.0* 


26.4* 


Mean 


59.5± 


0.9 


35.7±0.4 


29.0±0.3 


Std. Dev. 


3.1± 


0.9 


1.7±0.5 


1.0±0.3 


C. V. 


5.2± 


1.0% 


4,8 ±0.9% 


3.4±0.7% 


P. E. 


±2.1 




±1.1 


±0.7 




Treatment No. 3 (Calcium carbonate) 




Pot Number 
17 


Total Dry Weights 
68.7* 


Peas in Pods 
38.6* 


Shelled Peas 
30.6* 


18 


70.5 




42.9 


34.6 


19 


70.6 




41.2 


33.6 


20 


70.2 




42.8 


36.5 


21 


67.0 




40.9 


33.3 


22 


65.0 




37.2 


31.6 


23 


69.1 




44.2 


36.6 


24 


61.3* 




36.5* 


29.2* 


Mean 


68.7±0.6 


41.5±0.6 


34.4±0.5 


Std. Dev. 


2.1±0.6 


2.2±0.6 


1.8±0.5 


C. V. 


3.1±0.6% 


5.3±1.0% 


5.2±1.0% 


P. E. 


±1.4 




±1.5 


±1.2 




Treatment No. 


4 (Superphosphate of lime) 


Pot Number 
25 


Total Dry Weights 
58.5 


Peas in Pods 
35.8 


Shelled Peas 
29.7 


26 


60.4 




36.4 


29.7 


27 


56.3* 




34.2* 


27.4* 


28 


68.5 




40.8 


32.6 



Omitted from average. 



1922] 



Burgess: Studies on Marsh Soil Unproductive for Peas 





TABLE X- 


-(Continued) 




Pot Number 


Total Dry Weights 


Peas in Pods 


Shelled Peas 


29 


61.8 


36.5 


29.9 


30 


68.6 


40.0 


32.0 


31 


69.1 


37.8 


30.5 


32 


60.4* 


33.4* 


27.8* 


Mean 


64.5±1.2 


38.0±0.5 


30.7±0.3 


Std. Dev. 


4.4±1.3 


1.9±0.5 


1.1±0.3 


C. V. 


6.8±1.3% 


5.0±0.9% 


3.6±0.6% 


P. E. 


±3.0 


±1.3 


±0.7 




Treatment No. 5 


(Sodium nitrate) 




Pot Number 


Total Dry Weights 


Peas in Pods 


Shelled Peas 


33 


59.2 


36.0 


28.7 


34 


59.9* 


32.1* 


24.3* 


35 


60.1 


36.9 


30.0 


36 


55.9 


33.0 


26.5 


37 


60.5 


35.2 


29.1 


38 


54.7 


33.4 


27.0 


39 


53.1* 


29.0* 


23.2* 


40 


55.0 


30.2 


25.0 


Mean 


57.6±0.7 


34.1±0.6 


27.7±0.5 


Std. Dev. 


2.4±0.7 


2.2±0.6 


1.7±0.5 


C. V. 


4.2±0.8% 


6.4±1.2% 


6.1±1.1% 


P. E. 


±1.6 


±1.5 


±1.2 




Treatment No. 6 I 


[Potassium sulfate) 




Pot Number 


Total Dry Weights 


Peas in Pods 


Shelled Peas 


41 


52.8 


33.1 


26.7 


42 


54.8 


31.4 


24.8 


43 


50.0* 


29.4* 


23.6* 


44 


50.6 


33.0 


26.2 


45 


56.6 


34.4 


27.7 


46 


52.3 


31.8 


25.9 


47 


58.6 


35.6 


30.6 


48 


54.8* 


29.6* 


24.5* 


Mean 


54.3±0.7 


33.2±0.4 


27.0±0.5 


Std. Dev. 


2.7±0.8 


1.4±0.4 


1.8±0.5 


C. V. 


5.0±0.9% 


4.2±0.8% 


6.6±1.2% 


P. E. 


±1.8 


±0.9 


±1.2 




Treatment No. 7 


(Super, plus K»S0 4 ) 




Pot Number 


Total Dry Weights 


Peas in Pods 


Shelled Peas 


49 


49.7* 


28.3* 


23.0* 


50 


47.8 


30.1 


25.5 


51 


47.4* 


23.3* 


18.6* 


52 


53.5 


31.3 


25.2 


53 


57.0 


33.1 


29.1 


54 


51.6 


31.2 


26.2 


55 


56.7 


33.2 


27.4 . 


56 


57.4 


34.8 


29.1 


Mean 


54.0±1.0 


32.3±0.4 


27.1±0.4 


Std. Dev. 


3.5±1.0 


1.6±0.5 


1.6±0.5 


C. V. 


6.5±1.2% 


4.9 ±1.0% 


5.9±1.2% 


P. E. 


±2.4 


±1.1 


±1.1 



Omitted from average. 



University of California Publications in Agricultural Sciences [Vol. 4 



TABLE X— (Continued) 
Treatment No. 8 (Super, plus CaC0 3 ) 



Pot Number 


Total Dry Weights 


Peas in Pods 


Shelled Peas 


57 


64.7 




41.0 




34.3 


58 


54.5* 




33.0* 




27.9* 


59 


62.8 




38.0 




32.4 


60 


55.9 




35.2 




30.4 


61 


54.9* 




33.0* 




28.2* 


62 


64.6 




42.7 




35.7 


63 


60.6 




39.1 




33.2 


64 


71.9 




48.2 




41.1 


Mean 


63.4± 


1.3 


40.7± 


1.1 


34.5±0.9 


Std. Dev. 


4.8 ± 


1.4 


4.1± 


1.2 


3.3±1.0 


G. V. 


7.5± 


1.4% 


10.1± 


1.8% 


9.6±1.8 


P. E. 


±3.2 




±2.8 




±2.12 




Dates sampled. 

Fig. 9. — Water-soluble materials dissolved from cropped sodium-nitrate-treated 
pot soils. 



Omitted from average. 



1922] 



Burgess: Studies on Marsh Soil Unproductive for Peas 



certain of these compounds, but they amount to relatively little. Let 
us observe the chart showing comparative yields (fig. .20), first taking 
up "Total Dry Weights" produced. Treatment No. 1 (checks) pro- 
duced lower yields than did any of the others, yet brief computations 
show that the differences between the checks and treatments 6 (K,S0 4 ) 
and 7 (K 2 S0 4 + superphosphate) are not significant, while the real 
difference between the cheeks and 5 (NaN0 3 ) is so slight (less than 2 




Dates sampled. 

Pig. 10. — Water-soluble materials dissolved from cropped potassium-sulfate- 
treated pot soils. 

grams) as to be well-nigh negligible. We are, however, justified in 
stating that liming to neutrality did actually increase the yields of 
peas in the greenhouse over the cheeks by nearly 35% ; that applica- 
tions of superphosphate, at the rate of one ton per acre, gave an 
increase of approximately 28% ; that the same amounts of super- 
phosphate and CaC0 3 when used together increased yields no more 
than did either when added separately; and that gypsum at the rate 
of one ton per acre was about one-half as effective as CaC0 3 when the 
latter was used in sufficient quantities to neutralize soil acidity (8 tons 
per acre). It will be' recalled that, in the field, superphosphate alone 



372 University of California Publications in Agricultural Sciences [Vol. 4 

gave increased yields, while calcium carbonate, added to neutrality, 
had little effect. The comparative solubilities of the two, water being 
limited in the field, may well account for these differences. The final 
yields of dry matter obtained, however, do not show the comparative 
rates of growth nor do they reflect the conditions of the plants at the 
various monthly periods of sampling. During the entire experiment 




Dates sampled. 

Fig. 11. — Water-soluble materials dissolved from cropped pot soils receiving 
both superphosphate and potassium sulfate. 

the phosphate treated plants were apparently far ahead of all others 
in size, color, and general condition. They bloomed and set pods 
at least a week before the other treatments and matured ten days 
earlier than the others. The nitrate treated plants started well 
but soon fell behind. The lime treated plants made a slow, steady 
growth from the start, and, as will be seen, gave maximum yields 
both of total dry matter produced and of dry peas. Potassium sulfate 
wherever applied seemed at all times to retard growth. This may be 
due to the considerable quantity of sulfate-ion added, as the soil 
already carried nearly one-tenth of one per cent sodium sulfate. 
Gypsum also at first impeded growth. Figure. 21 gives one a good 



1922] 



Burgess: Studies on Marsh Soil Unproductive for Peas 



idea of the plants when the pods were setting (about one month 
before harvesting). It serves to compare the several treatments, an 
average pot from each series being taken in each case. 

Let us now consider the comparative weights of dried, shelled peas 
produced by the different salt applications (see fig. 20). The results 




Dates sampled. 

Fig. 12. — Water-soluble materials dissolved from cropped pot soils receiving 
both superphosphate and calcium carbonate. 

are slightly different from those considered above. The calcium car- 
bonate and the superphosphate treatments alone produced significant 
increases, while treatments of sodium nitrate and of potassium sulfate 
apparently decreased the yields, although the decreases are hardly 
significant. One can see from the data presented that liming to 
neutrality is the treatment par excellence for this soil type where 



374 University of California Publications in Agricultural Sciences [Vol. 4 

optimum moisture and temperature conditions obtain. The use of 
superphosphate without lime increases the yield of peas but 6%, 
while the addition of lime alone gives us an 18% increase over the 
check pots. In treatment 8, where both lime and superphosphate 
are applied, the yield is the same as where lime alone is used. The 
soil solubility studies to follow explain this point by showing that 
the calcium carbonate application renders soluble such amounts of soil 



m 1000 




Dates sampled. 

Fig. 13. — Effects of different treatments on specific resistances of water 
extracts. 



phosphorus that still further applications of this element are unneces- 
sary (see fig'. 18, curves 4 and 8). At no time during the develop- 
ment of the plants in the greenhouse was the presence of soil toxins 
in any way manifested. Certain other points of interest regarding 
comparative yields will be noted later in connection with the soil 
solubility studies. 

Immediately after harvesting (on April 10), the soils were care- 
fully removed from the pots and the roots examined for nodule pro- 
duction. Previous experience in the field had shown this soil to be 
well supplied with the strain of B. radicicola capable of producing 



1922] Burgess: Studies on Marsh Soil Unproductive for Peas 375 

nodules on pea roots. There was but little variation between the 
individual pots of the same treatment, the following general statements 
applying in each ease : 

Treatment No. 1 : A few large nodules. Several small ones per pot. 
Treatment No. 2: Similar to No. 1. Possibly a few more small 

nodules. 
Treatment No. 3 : A very few small nodules. But slightly better 

than No. 5. 
Treatment No. 4: Best of all treatments. Large numbers of 

nodules both large and small. Many near bottom of pots. 
Treatment No. 5 : No nodules found. 
Treatment No. 6 : Very large numbers of small nodules. No large 

clusters. 
Treatment No. 7 : Large numbers of nodules, chiefly small, al- 
though a few large clusters were noted. Almost as good as No. 4. 
Treatment No. 8 : Very few small nodules. Similar to No. 3. 
At first thought it might seem incredible that such an acid soil 
(P H 4.5) could harbor viable strains of B. radicicola. Fred and Daven- 
port, 12 however, in a series of very carefully controlled experiments, 
have given data to show that certain of the B. radicicola group are 
very resistant to acidity. All of the species apparently may withstand 
a reaction, in liquid media, of P H 5. They state : 

The nodule bacteria from different plants behave very differently toward acid. 
The legume bacteria may be divided into groups about as follows: 

1. Critical Ph — 4.9 Alfalfa and sweet clover. 

2. Critical Ph — 4.7 Peas and vetch. 

3. Critical Ph — 4.2 Clover and common beans. 

4. Critical Ph — 3.3 Soy and velvet beans. 

5. Critical Ph — 3.15 Lupines. 

The evidence supports the conclusions that a correlation exists between the acid 
resistance of the bacteria and the acid resistance of the higher plant. 

Since their bacteriological work was carried on in solution cultures, 
it may not be directly comparable with soil conditions, although it 
should be added that beans on the soil under experiment grow better 
than do either peas or alfalfa. This sequence would be expected from 
the data above presented. 

Upon further observance of the effect of the soil treatments on 
nodule formation, we note that where nitrates were added, no nodules 
appeared, and, contrary to expectation, where CaC0 3 was applied to 
neutrality but very few small nodules were found. The reason is 
probably the same in both eases (see fig. 19, curves 3, 5, and 8), 



376 University of California Publications in Agricultural Sciences [Vol. 4 

namely, a superabundance of nitrate-nitrogen. Many articles are ex- 
tant showing the depressing tendency of large amounts of soil nitrates 
on nodule formation. Superphosphate has often been observed to 
enhance nodule production. Our studies are in agreement with these 
findings. Potash and gypsum treatments but slightly enhanced 
nodule formation. 



- 










*B 










/ 












- / 














-*=* 


-■■asrae?^ 


•^■'■- "JZ^7' 


r==^zr===~s 




rS^§5=^"' 


2 










6 

7 



Dates sampled. 

Fig. 14. — Effects of different treatments on hydrogen-ion concentrations of 
soils. 



Soil Extraction Studies 

It remains for us to discuss the interesting data secured by periodi- 
cally extracting the differently treated soils with distilled water and 
noting the effects of both the fertilizer applications and the growing 
plants upon the concentration of soil solutes. The importance of 
knowledge of both the direct and the indirect effects of fertilizer chem- 
icals upon soils has been briefly pointed out in the introduction to 
these studies. Stewart 44 has shown very fully the effects of a growing, 
unfertilized crop of barley upon the concentration of the soil solution. 
During the first six to eight weeks, a considerable increase in soluble 
nutrients was usually observed. This was especially true of nitrates. 
The growing crop then began to draw heavily upon this store with the 



1922] 



Burgess: Studies on Marsh Soil Unproductive for Peas 



result that in most soils a gradual decrease in concentration was noted. 
He found that fertile soils were sometimes exceptions to this rule, the 
concentrations remaining practically constant throughout the entire 
growth period. The cause of this was pointed out as being doubtless 
due to the abilities of very fertile soils to renew soluble materials as 




Dates sampled. 
Fig. 15. — Effects of different treatments on calcium-ion solubility. 

rapidly as they were withdrawn. Hoagland, 21 Millar, 34 and McCool 
and Millar 32 have shown that the solutes in the soil solution vary 
greatly at different periods and are materially affected by the growth 
of plants. 

In the present investigation such effects are well shown in the 
curves presented in fig. 5. Upon the abscissae have been plotted the 
dates of sampling, while upon the ordinates appear the concentrations 



378 University of California Publications in Agricultural Sciences [Vol. 4 

of the various ions in parts per million of dry soil. Table' VIII lists 
the data from which these curves were constructed. The graphs 
represent results secured from the eight check pots which received no 
fertilizing materials. Only slight differences in water-soluble potas- 
sium, magnesium, calcium, and phosphorus are here shown at the 
different sampling dates, while during the last two months a gradually 
declining tendency is noticed. The absolute amounts of these elements, 




Dates sampled. 
Fig. 16. — Effects of different treatments on magnesium-ion solubility. 

present in a readily soluble form, are above those usually secured from 
the poor soils reported by Stewart, with the exception of P0 4 -ion, 
the amount of which is unusually low. The nitrate-ion gradually 
increased in quantity during the first two months of growth, then fell 
off until, at the time of crop maturity, none remained. The results 
of the chemical work as carried out on the untreated field plot soils 
(fig. 3) are in close agreement with the greenhouse checks, except that 
nitrates, in the field, at no time equal the large quantities at first 
present in the irrigated pot soils. 

Let us now briefly consider the effects of the several treatments 
upon the solubilities of the constituents of this clay loam soil. The 



1922] Burgess: Studies on Marsh Soil Unproductive for Peas 379 

check pots, which received no additions, will be taken as the basis for 
comparison. Both the cropped and fallowed soils will be discussed. 
The specific resistances of the soil extracts were always determined 
and are of importance in that they give us, in such dilute solutions, a 
comparative measure of total soluble salt concentrations. One-tenth 
of the specific resistance, in ohms, is shown by the solid lines in the 
graphs. It will be seen that these vary inversely with the concentra- 




Dates sampled. 
Fig. 17. — Effects of different treatments on potassium-ion solubility. 

tion of soil solutes and that a general relationship exists between water- 
soluble salts and crop production. 

Gypsum at the rate of one ton per acre was applied to the pots in 
treatment 2 (see fig. 6). Contrary to many general statements in the 
literature, nitrate production has not here been appreciably affected. 
The amount of water-soluble magnesium, however, has been increased 
almost threefold, while the amount of soluble potassium has been 
doubled under a rapidly growing crop. The amount of phosphate-ion 
was slightly increased at first, but soon fell to the level of the checks. 
Calcium, as would be expected, remained at a high level throughout 
the experiment. Sulfates, occasionally determined but not shown in 



380 University of California Publications in Agricultural Sciences [Vol. 4 

the graphs, were highest in the gypsum treatments. In the fallowed 
soils (Table IX), the results were much the same, except that the high 
level of concentration occurred a little later for all of the ions except 
magnesium. Here there was a gradual progressive increase. The 
actual concentrations of water-soluble compounds in the fallowed soils 
in all cases reached much higher levels than were reached in the 
cropped pots. 




Dates sampled. 
Fig. 18. — Effects of different treatments on phosphate-ion solubility. 

The CaC0 3 applications increased nitrate production (from soil 
nitrogen) at least threefold throughout the growing period (see fig. 7). 
The same is true of the production of soluble magnesium. . Soluble 
potassium and phosphorus are each increased by approximately 50 
per cent. Calcium, in a readily water-soluble form, has been increased 
from an average of 40 p. p. m. in the cheeks to over 300 p. p. m. in the 
lime-treated pots. The specific resistance of the soil extract is very low 
throughout. With the exception of nitrate (and this tendency is also 
shown in the uncropped soil) the lime treatment not only maintains 
the concentrations of the several ions during the period of vigorous 
absorption of solutes, but actually increases the rate of solubility of 



1922] 



Burgess: Studies on Marsh Soil Unproductive for Peas 



minerals over and above crop demands, for we see that, on March 20, 
at the time of maturity there is shown a slight rise in the phosphorus, 
potassium, magnesium, and calcium curves over the previous sampling 
date. It will be recalled that the CaC0 3 treated pots produced the 
maximum crops. In the fallowed soil (Table IX), the carbonate 
treatment produced by far the largest amount of soluble material, as 
shown by the specific resistances. In this case, also, the greatest con- 




Dates sampled. 
Fig. 19. — Effects of different treatments on nitrate-ion solubility. 

centration of solutes appeared some weeks later than in the cropped 
soil. Magnesium was an exception. Here progressive solubility was 
gradual throughout. In both cropped and fallowed soils, gypsum 
and calcium carbonate were about equally effective in increasing mag- 
nesium solubility. A simple interchange of bases may possibly account 
for this. The solubility of the soil potassium is affected but slightly 
by the CaC0 3 additions. 

Figure 8 shows the effect of superphosphate treatment. Figure 4, 
which records similar data for the field plots, may also here be of com- 
parative interest. A notable similarity is shown between the two. A 
comparison of figure 8 with the check pots, figure 5, shows the addition 



382 University of California Publications in Agricultural Sciences [Vol. 4 

of superphosphate to have practically doubled the amounts of water- 
soluble phosphorus, calcium, and magnesium, throughout the duration 
of the experiment, while nitrate formation, contrary to expectation, 
was slightly depressed by it. The same holds true, in the case of 
nitrates, for the fallowed soils, although nitrification in both cases 
increased at first more rapidly in the presence of the soluble phos- 
phorus. In this series the cropped and uncropped soils behaved very 
similarly as regards progressive solubility ; the soil, when receiving an 
application of acid phosphate, apparently being able to maintain the 
important solutes at fairly high concentrations during crop with- 
drawals. 

The results for the NaN0 3 treatment are shown in figure 9. With 
the exception of the large amount of added nitrate, there is little 
difference between these soils and the checks. Thus, the nitrate appli- 
cation has had very little effect in increasing the solubility of this 
soil's constituents. This is in accordance with the recent work of 
Bauer, 3 who found that the presence of NaN0 3 had no effect upon the 
availability of soil phosphorus, and of Jensen, 23 who concluded that 
nitrate applications had no effect upon potassium availability and 
actually decreased a soils soluble phosphate content. Spurway, 43 on 
the other hand, shows additions of NaN0 3 to considerably increase 
the solubility of phosphorus and magnesium in the sandy soils which 
he investigated. The increases, however, are irregular, and the con- 
ditions imposed are most artificial. The fallowed soils receiving NaN0 3 
gave increases over the checks, although the increments were small in 
comparison with those noted for other treatments. The crop results 
further showed that nitrate applications were unwarranted. The 
specific resistances were here at first slightly lower than were those 
of the checks, due to the soluble nitrate application, but even this 
difference disappeared as the end of the growing period was reached. 

The potassium sulfate application, although slightly increasing 
water-extractable soil materials, also had no enhancing effect upon 
yields. It was applied at the rate of 500 pounds per acre. Figure 10 
shows that water-soluble lime and potash have each been slightly 
increased during the period of active growth. The solubility of the 
phosphorus has been unaffected, as has nitrate production. Mag- 
nesium has been increased. The results secured with potassium 
sulfate in the fallowed soil are in fair agreement with these. The 
general relationships hold, although slightly larger quantities of solutes 
appear in all cases. A slow progressive solubility is recorded for each 



1922] Burgess: Studies on Marsh Soil Unproductive for Peas 383 

ion determined except calcium, which apparently assumes its maximum 
concentration about a month or six weeks after the addition of the 
potassium sulfate and thereafter gradually declines. None of the 
solubility increases is marked. 

In treatment 7, superphosphate (one ton per acre), together with 
potassium sulfate (500 pounds per acre), was added. The effects 
upon the solubility of the various ions determined are shown in figure 
11. As would be expected, the soluble salt content has been consider- 
ably increased. Nitrates, however, remain approximately as in the 
check pots. No uncropped soils carrying two-salt treatments were 
maintained. The yields here were a surprise — much below those 
where superphosphate alone had been used. This may be due to 
"alkali," for analysis showed that Na 2 S0 4 was present slightly in 
excess of 0.2 per cent. Improper balance of salts may also be advanced 
as a p'ossible explanation for the lowered yields, as sulfate, calcium, 
magnesium, and potassium-ions are present in large quantities, while 
nitrates are present in relatively low amounts. 

In the last series, applications of superphosphate and CaC0 3 were 
the treatments employed. The concentrations of the soil extracts were 
decidedly increased (see fig. 12), as shown by the conductivity meas- 
urements. The Ca-, N0 3 -, and P0 4 -ions especially showed greatly 
increased solubility. No tendency toward a decline in concentration 
during the period of rapid growth was evident. That soluble phos- 
phate applications are superfluous when this soil is neutralized with 
lime is shown in figure 7. The ability of CaC0 3 to set free soluble 
phosphorus from soil minerals has also been recorded by Fraps, 11 
Hartwell and Kellogg, 10 Guthrie and Cohen, 14 and others. 

In order to compare more easily the effects of the individual treat- 
ments upon the solubility of each ion, a second series of curves was 
prepared. The complete hydrogen-ion and conductivity data are also 
presented. Let us glance at figure 13, which shows the effects of each 
treatment (1 to 8) upon the periodically determined specific resist- 
ances. The determination of specific resistance upon soil extracts is 
at the present time meeting with considerable favor among soil investi- 
gators. In alkali studies, where large numbers of soils must be ex- 
amined for total soluble salts, its use is certainly to be recommended. 
That considerable precision may be claimed for it has been shown by 
von Horoath, 22 who has proposed a soil classification based upon elec- 
trical conductivity. In figure 13, the high concentrations of treatments 
8 and 3 (where CaC0 3 was added) over the entire growth period are 






384 University of California Publications in Agricultural Sciences [Vol. 4 

well shown, while the low concentrations of the checks (1), the K,S0 4 
pots (6), and the nitrate treated soils (5), are likewise emphasized. 
Numbers, 2, 4, and 7 occupy intermediate positions. That the yields 
may be closely correlated with soluble salt concentrations (conduc- 
tivities) has been previously noted. A comparison with figure 20 
emphasizes this fact. 

Considerable interest attends the data presented in figure 14. 
Hydrogen-ion determinations were made periodically upon these 
pot soils throughout the experiment, much care being taken to secure 
accurate, comparative results. It was desired to ascertain whether or 
not, during the growth of the crop, any of the fertilizer treatments, 
except, of course, CaC0 3 , had in any way altered soil reaction, and 
also whether or not, after adding CaC0 3 to neutrality, any acidity 
subsequently developed. The abscissa shows the dates of sampling, 
while the ordinate is divided into the customary P H units. The" small, 
ten-gram samples used in making these determinations were carefully 
taken from the large monthly composite samples and were repre- 
sentative. The determinations were made upon the moist soils as 
soon as received from the greenhouse. A study of figure 14 shows 
that in treatments 3 and 8, sufficient CaC0 3 had been added to main- 
tain an alkaline reaction (above Ph7), although the tendency to 
gradually decrease in alkalinity is shown at the last two sampling dates. 
While exactly the same amounts of CaC0 3 were supplied in both cases, 
it will be seen that the addition of superphosphate in treatment 8 
rendered this soil more alkaline at all times. The same tendency to 
induce alkalinity is shown where superphosphate is added alone 
(compare treatment 3 with treatment 1), the checks being the most 
acid soils of all. These results are in direct agreement with those of 
Conner, 8 who has shown that soils that had been treated with acid 
phosphate for twenty years were less acid than the untreated soils. 
Morse 38 has determined hydrogen-ion concentrations colorimetrically 
on certain plot soils. In agreement with other investigators, he claims 
that acid phosphate, even though used over a long period of years, 
produced no noticeable effect on soil reaction, while, where lime was 
occasionally used with it, at the rate of one ton per acre, the super- 
phosphate apparently further enhanced alkalinity. Small, definite 
differences also existed between the checks and the soils receiving the 
neutral salt treatments. It will be seen that the K 2 S0 4 application 
has decreased the hydrogen-ion concentration throughout by at least 
three-tenths of a P H — an amount too great to be considered experi- 



1922] Burgess: Studies on Marsh Soil Unproductive for Peas 385 

mental error. This basic tendency of the other salts, while less pro- 
nounced, is, however, uniform and definite. 

A decided upward trend of all of the curves (except 3 and 8) is 
noticeable from February 20 to March 20. The decreases in hydrogen- 
ion concentration are here too marked to be ascribed to error. A pos- 
sible explanation for this is as follows: At the end of the growing 
season, a small fraction only of the nitrate still remains in these very 
acid soils (see figure 19). The soil solution must be practically 
saturated with CO, due to rapid root growth and high organic matter 
content. When the large amounts of nitrate are absorbed and removed 
from solution, the bases formerly associated with this strongly acid 
radical may combine with the weak H 2 C0 3 forming bicarbonates of 
the strong bases (K, Na, Ca). Subsequent hydrolysis tends slightly to 
increase OH-ion concentration. 

Another point which the writer deems of importance in connection 
with the reaction studies recorded is that strong soil acidity, per se, 
is not necessarily harmful to growth, and that it has in the past been 
over-emphasized as a cause of low productivity, especially in the case 
of leguminous crops. A glance at figure 21, together with the high 
yields secured in all cases, checks included, suffices to show that, even 
where such a "lime loving" legume as the pea is grown, other con- 
ditions being optimum, good results may be expected in the presence 
of high soil acidity. So far as the writer is aware there is no definite 
evidence in the literature to show that soil acidity of itself is the 
direct cause of infertility. Recent work at the University of Cali- 
fornia might be cited to show that heavy yields are often secured in 
solution cultures where hydrogen-ion concentrations are abnormally 
high. It is thus questionable whether complete neutralization, espe- 
cially where high lime applications are necessary, is ever justified. 
Many cases have been noted where the satisfaction of a small fraction 
of the so-called "lime requirement" has increased yields to the same 
extent as have larger lime treatments. 

The comparative calcium-ion concentrations in the variously treated 
soils appear in figure 15. In treatment 8, receiving both CaC0 3 and 
superphosphate, we find the most soluble calcium. This is followed 
by CaC0 3 , gypsum, superphosphate plus K 2 S0 4 , and superphosphate 
alone. The K 2 S0 4 and the NaN0 3 treatments had little effect in 
setting free soil calcium. 

The behavior of magnesium-ion is of interest in that it follows 
closely that of calcium-ion solubility. A comparison of figure 16 with 



386 University of California Publications in Agricultural Sciences [Vol. 4 

figure 15 shows that there are no exceptions to this statement. As 
magnesium was in no case applied to the soils* in soluble form, there 
must have been a direct exchange of bases between this ion and those 
supplied in the treatments. 

The solubility of soil potassium has been fully discussed. A 
direct graphical comparison of the treatments is shown in figure 17. 
The check soils (number 1) are the lowest in available potassium 
throughout, while, aside from the direct K 2 S0 4 treatments, gypsum is, 
in the soil under study, apparently superior to all others in setting 
free potash. The efficacy of the superphosphate additions is here 
doubtless due to this ingredient. Recent work of McCool and Millar 33 
bears out this statement. Calcium carbonate is much less effective. 
Slight increases only result from the NaN0 3 applications. 

The percentage of water-soluble phosphate is unusually low in 
this soil and none of the treatments, except those directly supplying 
phosphate-ion, greatly alters its availability save CaC0 3 which has a 
slightly enhancing tendency toward the end of the experimental period. 
The check soils are a little below the others in the amounts of soluble 
phosphorus they contain, as shown in figure 18, although the differ- 
ences are slight. That low concentrations of P0 4 -ion are the rule in 
water extracts of soils has often been recorded. Certain data recently 
secured by the writer have shown that the same holds for the true 
soil solution as obtained by a direct pressure method. One to three 
p. p. m. of soil solution are here usually found. "Work in this con- 
nection has been reported elsewhere.! 

The nitrate-ion concentrations as plotted in figure 19 are of interest 
in that they closely agree with nitrification studies (not here reported) , 
Except number 5, where NaN0 3 was directly supplied, the CaC0 3 
treatments alone gave noteworthy increases. In all cases, however, 
sufficient nitrification may have taken place within this acid soil to 
supply crop requirements, although it should be recalled that a legu- 
minous crop was grown. 

"While the results of these solubility studies apply to this soil alone, 
we are probably safe in considering them generally applicable to 
transported, low-lying acid clays and clay loams, comparatively high 
in organic matter and rich in nitrogen. 



* The superphosphate alone gave slight traces, 
f See Soil Science, vol. 13. 



1922] Burgess: Studies on Marsh Soil Unproductive for Peas 



SUMMARY 

The work herein reported embraces an investigation of an acid, 
marsh soil, unproductive for peas, by the use of certain of the more 
modern procedures. Both field and greenhouse experiments were con- 
ducted, a variety of fertilizing materials were employed, and soil- 
water-extracts, periodically made, were studied to ascertain the rates 
of formation, as well as the absolute amounts, of soluble salts formed 
in the soil when influenced by the different factors involved. This 
work has been supplemented by hydrogen-ion determinations and con- 
ductivity measurements. A detailed discussion of the results secured 
has been given in the body of the text, although a critical study of 
the data presented offers several points of theoretical interest. 

Doubtless, the most important point made, aside possibly from the 
effects of the various treatments upon yields, is the remarkable indirect 
fertilizing action of certain of the chemical compounds when applied 
to this cropped, clay-loam soil. That this has been brought about by 
a process of ionic substitution, element for element, within the 
hydrated silicate molecules, thereby greatly increasing mineral solu- 
bility, is a probable explanation. Why certain bases, as calcium for 
instance, should be more active than sodium or potassium or why the 
SO. r ion should be more reactive than either N0 3 -ion or P0 4 -ion are 
questions offering a good field for hypothesis and experiment. 

In comparing field and greenhouse yields we see that while CaC0 3 
had no effect whatever in the field, in the pot experiment it gave the 
largest crop. With superphosphate the results were reversed. As 
this was an unusually dry year in the field, while in the greenhouse 
moisture conditions were maintained at optimum, an explanation may 
possibly lie in the comparative solubilities of these two compounds. 
The action of the CaC0 3 , being in large part due to its indirect effect 
through enhanced nitrification, requires considerable quantities of 
water, while, on the other hand, if sufficient moisture is present to 
dissolve but a small portion of the superphosphate, enhanced yields 
should result in a soil deficient in available phosphorus. Another 
effect of the field application of acid phosphate was to increase per- 
manently the solubilities of all of the soil constituents except P0 4 -ion. 
Soluble phosphorus was directly supplied, yet at the end of two 
months no indications of such applications were apparent in the water 



388 



University of California Publications in Agricultural Sciences [Vol. 4 



extracts. Similar conditions were observed in the greenhouse pot 
soils. It has been noted that small quantities (12 to 14 p. p. m.) of 
soluble aluminum were consistently found in this soil. A simple 
explanation of rapid phosphate reversion may thus be found in a 
direct union between superphosphate and soluble aluminum, with 
the formation of insoluble aluminum phosphate. In a soil rendered 
alkaline with lime, however, no such reaction could occur due to the 
precipitation of all soluble aluminum, either as the hydroxide or as 
































K 


































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±3.6 






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t 




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j m 


























it 




























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±1.5 






±2.7 




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i 








±0.S 












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in 


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Tn£A TMENTS _ 



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Fig. 20. — Comparative yields per pot of total dry matter and cured peas. 



calcium aluminate, 36 as well as to the early formation of the reverted 
calcium phosphate which, so far as crops are concerned, is largely 
available. Such conditions do obtain in the CaC0 3 -treated pots where 
maximum yields were registered and where moisture conditions were 
optimum. The curves here also show a slightly enhanced phosphate 
solubility which is maintained throughout the growing period. 

A careful study of figures 5, 7, 11, and 12, together with compara- 
tive yields for these treatments (figure 20), casts some doubt as regards 
the power of soluble phosphorus to increase yields greatly in this 
soil unless soluble calcium also is present in adequate amounts. In 
figure 11 (superphosphate + K 2 SOJ fairly large quantities of 
soluble P0 4 -ion obtain (in fact, larger than appear in the CaC0 3 - 



1922] 



Burgess: Studies on Marsh Soil Unproductive for Peas 



treated pots), yet the yields are greatly in favor of the CaC0 3 addi- 
tions. Large percentages of soluble calcium are shown at all times in 
figure 7. In figure 11, however, less than one-half of these amounts 
is present, while magnesium-ion concentration in this case is almost 
equal to that of calcium-ion. These results may show that a certain 
balance of ions within soil solutions is essential for optimum plant 
growth. 




Fig. 21. — Plants one month before harvesting, showing the eight treatments. 

Similar indications of the necessity for proper ionic ratios are 
shown in figures 7 and 9 where nitrates, phosphates, potassium, and 
calcium may be compared. The proportion of nitrates is high in 
both cases ; the amounts of phosphates differ but 1 to 2 p. p. m., as is 
also the ease with potassium, but calcium-ion is increased sixfold in 
the CaC0 3 treatment where the maximum yields are recorded. Other 
examples might be given whidh indicate that where anions are high, 
cations must also be present in certain definite optimum proportions. 

A glance at the periodical conductivity measurements on the 
extracts from the variously treated soils shows that they arrange them- 
selves exactly in the order of productivity. This method has been 
shown to be of great value in the study of alkali soils where large 
quantities of soluble salts prevail. May it not be of still greater value, 
in the absence of alkali, where estimates of comparative fertility are 
desired ? 



,390 University of California Publications in Agricultural Sciences [Vol. 4 

Soil acidity has been fully discussed in the light of data here pre- 
sented and, except in the presence of unusually high hydrogen-ion 
concentrations (below P H 4.5), it seems doubtful to the writer that 
acidity, per se, is ever the direct cause of low productivity provided 
sufficient concentrations of the basic ions (Ca, Mg, K) are present 
within the soil solution. 



CONCLUSIONS 

The following general conclusions may be drawn as the result of 
these investigations : 

These studies were carried out on an acid, drained, heavy clay- 
loam, marsh soil of the San Francisco Bay region which was unpro- 
ductive for certain crops and carried small percentages of the white 
alkali salts, notably sulfates. 

Nitrification studies showed that the addition of calcium carbonate 
to neutrality greatly increased nitrate production, while soluble phos- 
phorus and potassium compounds, without lime, produced no effect. 
Ammonification was largely due to soil fungi, and the Azotobacter 
species were absent. 

A statistical study of the factor of variability, where certain water- 
soluble ions within soil extracts were taken as the criteria, showed that 
apparently uniform field soils may vary greatly within small areas; 
this is in accordance with the recent work of Waynick and Sharp. 48 

In the field, water was apparently the limiting factor in crop pro- 
duction at the Marin Meadows Ranch during the 1919-1920 season. 
Under those conditions superphosphate applied at the rate of one ton 
per acre increased yields by approximately 25 per cent while liming 
to neutrality gave no increases over the check plots. The chemical 
control maintained throughout the duration of the field experiment 
showed that the acid-phosphate applications had greatly enhanced the 
solubility of soil K, Mg, and Ca, while nitrate production was affected 
but slightly. The rapid revision of soluble phosphate within this soil 
was thought to be due largely to the formation of aluminum phosphate, 
for a small amount of aluminum-ion was always present in water 
extracts of this soil. Ferrous compounds or other toxic materials 
aside from the white alkali salts were not found. 

In the greenhouse, where moisture and temperature conditions 
were optimum, much larger plants were produced. A 35% increase 



1922] Burgess: Studies on Marsh Soil Unproductive for Peas 391 

(over the checks) in yield of total dry matter attended the use of 
CaC0 3 , when added to neutrality, and a 28% increase where super- 
phosphate at the rate of one ton per acre was applied. The soils 
receiving- gypsum treatments and the checks were about equal in pro- 
ductivity, while NaN0 3 , and K 2 S0 4 , each supplied at the rate of 500 
pounds per acre, gave slight but insignificant losses. The yields of 
dried peas followed in a similar order. 

Nodule formation as affected by these treatments within this very 
acid soil is discussed. Nitrates completely inhibited it, while CaC0 3 
added to neutrality acted similarly (due doubtless to greatly enhanced 
nitrification) . The application of soluble phosphorus increased nodule 
formation while potassium sulfate and gypsum produced no noticeable 
effects. 

All of the chemical compounds added increased the concentration 
of the soil solutions under the growing crops when compared with the 
untreated checks, although marked differences between the several 
treatments were noted. A direct relationship existed between the con- 
centration of solutes present in the soil extracts, as shown by con- 
ductivity measurements, and crop production. Gypsum was the most 
active liberator of the soil potassium and was equal to any other 
compound in effecting the solution of soil magnesium, while its action 
upon phosphorus availability and upon nitrate formation was nil. 
Calcium carbonate, when added to neutrality, was apparently the 
most effective soil solvent supplied, although its action was probably 
largely indirect. It occupies first place in effecting the solution of 
all ions, except potassium. In comparison with the checks, specific 
resistance was here decreased by almost one-half. This is doubtless 
due to the intensive nitrification which this treatment engenders. 
Nitrate production (from soil N) was nearly trebled, as was water 
soluble magnesium. Soluble calcium was increased many fold, and 
soluble K and P0 4 were each increased by at least one-third. With 
the possible exception of nitrate-ion concentration, which likewise fell 
off in the fallowed soil, there was no declining tendency noticed on the 
part of any of the nutritive ions during maximum withdrawals by 
the heavy pea crop produced. 

The enhanced solubility of soil minerals due to superphosphate 
applications is probably largely to be attributed to the gypsum which 
this material contains. Bearing in mind that approximately twice as 
much calcium was supplied in the gypsum treatments, the similarity 
between the two is strikingly shown in figures 6 and 8. Soluble 
phoshorus, of course, was directly supplied in the superphosphate. 



392 University of California Publications in Agricultural Sciences [Vol. 4 

Sodium nitrate had little effect upon this soil's solubility in water 
throughout the duration of the experiments here reported. 

Potassium sulfate applications increased the amounts of Ca and 
Mg going into solution by possibly one-third, while nitrate formation 
and phosphate availability were apparently unaffected. 

The results secured from the two-salt applications, both as regards 
yields and soil solubilities, were approximately the same as the average 
of the similar individual single-salt treatments. 

A periodical study of hydrogen-ion concentration was carried out 
on each of the differently treated pot soils throughout the cropping 
period. All of the soils to which neutral salts had been applied were 
slightly but consistently less acid than were the checks, superphosphate 
especially tending to lower H-ion concentration. During heavy nitrate 
absorption there was a slow, definite increase in soil alkalinity. On 
the other hand, where calcium carbonate had been added to neutrality, 
a progressive increase in H-ion concentration was recorded. The ques- 
tion is discussed as to whether soil acidity, per se, is ever a direct cause 
of impaired productivity. 

The results, when cropped and fallowed soils were compared, 
differed but slightly, the chief dissimilarity being that the water 
extracts of the fallowed soils reached maximum concentrations about 
a month later than did those of the cropped soils, and thereafter 
remained stationary or gradually decreased. Larger amounts of 
solutes were, as a rule, present in the uncropped soils but the same 
comparative relationships almost invariably held. A series of fal- 
lowed soils is therefore held to be here superfluous, little additional 
information being gained, while the labor involved is approximately 
doubled. 

In conclusion, the writer wishes to express his indebtedness to 
Professor C. B. Lipman, under whose direction this work was done. 
Thanks for many helpful suggestions and criticisms are also due 
Professor D. R. Hoagland and Professor W. P. Kelley. 



1922] Burgess: Studies on Marsh Soil Unproductive for Peas 



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1922] Burgess: Studies on Marsh Soil Unproductive for Peas 395 

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vol. 18 (Supp. no. 7), pp. 15-37, fig. 2. 



UNIVERSITY OF CALIFORNIA PUBLIC ATIONS— (Continued) 

6. The Effect of Several Types of Irrigation Water on the Ph Value and Freez- 

ing Point Depression of Various Types of Soils, by Dr. R. Hoagland and 

A. W. Christie. Pp. 141-157. November, 1919 .25 

7. A New and Simplified Method for the Statistical Interpretation of Bio- 

metrical Data, by George A. Linhart. Pp. 159-181, 12 text figures. Sep- 
tember, 1920 --.-.■ 25 

8. The Temperature Relations of Growth in Certain Parasitic Fungi, by 

Howard S. Fawcett. Pp. 183-232, 11 text figures. March, 1921 .75 

9. The Alinement Chart Method of Preparing Tree Volume Tables, by Donald 

Bruce. Pp. 233-243. December, 1921 20 

10. Equilibrium Studies with Certain Acids and Minerals and their Probable 

Relation to the Decomposition of Minerals by Bacteria, by Douglas 
Wright, Jr. Pp. 245-337, 35 text figures. March, 1922 1.25 

11. Studies on a Drained Marsh Soil Unproductive for Peas, by Paul S. Burgess. 

21 text figures. June, 1922 '. 65 

AGRICULTURE.— The Publications of the Agricultural Experiment station consist of Bul- 
letins and Biennial Reports edited by Professor Thomas Forsyth Hunt, Director of 
the Station. These are sent gratis to citizens of the State of California. For 
detailed information regarding them address the Agricultural Experiment Station, 
Berkeley, California. 
BOTANY— W A. Setchell, Editor. Volumes I-IV $3.50 per volume; volume V and follow- 
ing $5.00 per volume. Volumes I (pp. 418), H (pp. 360), IDE (pp. 400), IV (pp. 397), 
and IX (pp. 423) completed. Volumes VL VII, VIII, X in progress. 
Vol. 5. 1. Studies in Nicotiana. I, by William A. . Setchell. Pp. 1-86, plates 1-28. 

December, 1912 r - ~- * 1-25 

2. Quantitative Studies of Inheritance in Nicotiana Hybrids, by Thomas H. 

Goodspeed. Pp. 87-168, plates 29-34. December, 1912 1.00 

3. Quantitative Studies of Inheritance in Nicotiana Hybrids. II, by Thomas 

H. Goodspeed. Pp. 169-188. January, 1913 - 20 

4. On the Partial Sterility of Nicotiana Hybrids made with N. sylvestris as a 

Parent, by Thomas H. Goodspeed. Pp. 189-198. March, 1913 .10 

5. Notes on the Germination of Tobacco Seed, by Thomas Harper Goodspeed. 

Pp. 199-222. May, 1913 - -----»- - - 25 

6. Quantitative Studies of Inheritance in Nicotiana Hybrids. Ill, by Thomas 

Harper Goodspeed. Pp. 223-231. April, 1915 ---- .1° 

7. Notes on the Germination of Tobacco Seed. II, by Thomas Harper Good- 

speed. Pp. 233-248. June, 1915 - 15 

8. Parthenogenesis, Parthenocarpy, and Phenospermy in Nicotiana, by Thomas 

Harper Goodspeed. Pp. 249-272, plate 35. July, 1915 25 

9 On the Partial Sterility of Nicotiana Hybrids made with N. sylvestris as a 
Parent. XI, by T. H. Goodspeed and A. H. Ayres. Pp. 273-292, plate 36. 
October, 1916 --• ------; • 20 

10. On the Partial Sterility of Nicotiana Hybrids made with N. sylvestris as a 

Parent. IH. An Account of the Mode of Floral Abscission in the F, 
Species Hybrids, by T. H. Goodspeed and J. N. Kendall. Pp. 293-299. 
November, 1916 ----- • ■- -.- --■ - 05 

11. The Nature of the F, Species Hybrids between Nicotiana sylvestris and 

Varieties of Nicotiana Talacum, with Special Reference to the Conception 
of Reaction System Contrasts in Heredity, by T. H. Goodspeed and R. E. 

Clausen. Pp. 301-346, plates 37-48. January, 1917 45 

12 Abscission of Flowers and Fruits in Solanaceae with Special Reference to 

Nicotiana, by John N. Kendall. Pp. 347-428, plates 49-53. March, 1918 .85 

13. Controlled Pollination in Nicotiana, by Thomas H. Goodspeed and Pirie 

Davidson. Pp. 429-434. August, 1918 _ - ■-■ - 10 

14. An Apparatus for Flower Measurement, by T. H. Goodspeed and R. E. 

Clausen. Pp. 435-437, plate 54, 1 text figure. September, 1918 05 

15 Note on the Effects of Illuminating Gas and its Constituents in Causing 

Abscission of Flowers in Nicotiana and Citrus, by T. H. Goodspeed, J. M. 

McGee, and R. W. Hodgson. Pp. 439-450. December, 1918 15 

16. Notes on the Germination of Tobacco Seed. HI. Note on the Relation of 

Light and Darkness to Germination, by T. Harper Goodspeed. Pp. 451- 

455. April, 1919 ■•--"- ---- 

17 Studies of Inheritance in Nicotiana Tabacwm. I. A Report on the Results 

of Crossing Certain Varieties, by W. A. Setchell, T. H. Goodspeed, and 

R. E. Clausen. Pp. 457-521. March, 1922 _ 1-25 

Vol. 6. 1. Parasitic Florideae. I, by William Albert Setchell. Pp. 1-34, plates 1-6. 

April, 1914 ■ - ..........~..J-~. : .~~ .35 

2. Phytomorula regularis, a Symmetrical Protophyte related to Coelastrum, by 

Charles Atwood Kofoid. Pp. 35-40, plate 7. April, 1914 05 

3. Variation in Oenothera ovata, by Katherine Layne Brandegee. Pp. 41-50, 

plates 8-9. June, 1914 — - ,10 



LIBRARY OF CONGRESS 



002 672 843 5 
UNIVERSITY OF CALIFORNIA PUBLICATIONS— (Continued) 

4. Flantae Mexicanae Purpusianae. VI, by Townshend Stith Brandegee. Pp. 
51-77. August, 1914 , _ _ .25 

5. The Scinaia Assemblage, by William A. Setchell. Pp. 79-152, plates 10-16. 
October, 1914 __ .75 

6. Notes on Pacific Coast Algae. I. Pylaiella Postelsiae, n. sp., a New Type 
in the Genus Pylaiella, by Carl Skottsberg. ' Pp. 153-164, plates 17-19. 
May, 1915 ._. .10 

7. New and Noteworthy Calif ornian Plants. II, by Harvey Monroe Hall. Pp. 
165-176, plate 20. October, 1915 J.0 

8. Plantae Mexicanae Purpusianae. VH, by T. S. Brandegee. Pp. 177-197. 
October, 1915 20 

9. Floral Relations among tie Galapagos Islands, by A. L. Kroeber. Pp. 199- 
220. March, 1916 '. .20 

10. The Comparative Histology of Certain Californian Boletaceae, by Harry 
S. Yates. Pp. 221-274, plates 21-25. February, 1916 50 

11. A Revision of the Tuberales of California, by Helen Margaret Gilkey. Pp. 
275-356; plates 26-30. March, 1916 . .80 

12. Species Novae vel Minus Cognitae, by T. S. Brandegee. Pp. 357-361. April, 
1916 1 _ : 05 

13. Plantae Mexicanae Purpusianae. VIIIj by Townshend, Stith Brandegee. 
Pp. 363-375. March, 1917 15 

14. New Pacific Coast Marine Algae. J, by Nathaniel Lyon Gardner. Pp. 377- 
416, plates 31-35. June, 1917 ...._ . _ 40 

15. An Account of the Mode of Foliar Abscission in Citrus, by Robert W. 
Hodgson. Pp. 417-428. February, 1918 :. 10 

16. New Pacific Coast Marine Algae. H, by Nathaniel Lyon Gardner. Pp. 
429-454, plates 36-37. July, 1918 . „ __ _ 25 

17. New Pacific Coast Marine Algae. Ill, by Nathaniel Lyon Gardner. Pp. 
455-486, plates 38-41. December, 1918 35 

18. New Pacific Coast Marine Algae. IV, by Nathaniel Lyon Gardner. Pp. 
487-496, plate 42. January, 1919 10 

19. Plantae Mexicanae Purpusianae. IX, by Townshend Stith Brandegee. 
Pp. 497-500. November, 1919 _ 05 

. 7. 1. Notes on the California Species of Trillium L. A Report on the General 
Results of Field and Garden Studies, 1911-1916, by Thomas Harper Good- 
and Robert Percy Brandt. Pp. 1-24, plates 1-4. October, 1916 25 

2. (The same.) The Nature and Occurrence of Undeveloped Flowers, by 
Thomas Harper-Goodspeed and Robert Percy Brandt. Pp. 25-38, plates 
5-6. October, 1916 15 

3. (The same.) Seasonal Changes in Trillium Species with Special Reference 
to the Reproductive Tissues, by Robert Percy Brandt. Pp. 39-68, plates 
7-10. December, 1916 .. _ _ .30 

4. (The same.) Teratological Variations of Trillium sessile var. giganteum, by 
Thomas Harper Goodspeed. Pp. 69-100, plates 11-17. January, 1917 30 

5. A Preliminary List of the Uredinales of California, by Walter C. Blasdale. 
Pp. 101-157. August, 1919 _ _ 50 

6. A Rubber Plant Survey of Western North America. I. Chrysothamnus 
nauseosus and Its Varieties, by Harvey Monroe Hall and Thomas Harper 
Goodspeed; Pp. 159-181. 

7. (The same.) II, ChrysiL a New Rubber from Chrysothamnus nauseosus, by 
Harvey Monroe Hall. Pp. 183-264, plates 18-20, 6 figures in text. 

8. (The same.) m. The Occurrence of Rubber in Certain West American 
Shrubs, by Harvey Monroe Hall and Thomas Harper Goodspeed. Pp. 
265-278, 2 figures in text. 

Nos. 6, 7, and 8 in one coyer. November, 1919 1.25 

9. Phycological Contributions. I, by William Albert Setchell and Nathaniel 
Lyon Gardner. Pp. 279-324, plates 21-31. July, 1920 50 

10. Plantae Mexicanae Purpusianae. X, by Townshend Stith Brandegee. De- 
cember, 1920 10 

11. Phycological Contributions, II to VI. II, New Species of Myrionema; 
III, New Species of Composonema; IV, New Species of Hecatonema; 
V, New Species of Pylaiella and Streblonema; VI, New Species of Ecto- 
carpus, by William Albert Setchell and Nathaniel Lyon Gardner, Pp. 
333-426, plates 32-39. May, 1922. _ 1.50 

1. The Marine Algae of the Pacific Coast of North America. Part I. Myxo- 
, phyceae, by William Albert Setchell and Nathaniel Lyon Gardner. Pp. 

1-138, plates 1-8. November, 1919 _ 1.50 

2. (The same.) Part H. Chlorophyceae, by William Albert Setchell and 
Nathaniel Lyon Gardner. Pp. 139-374, plates 9-33. July, 1920 2.75 

A Report upon the Boreal Flora of the Sierra Nevada of California, by Frank 

Jason Smiley. 423 pages, 7 plates. October, 1921 5.00 



